ASP Introduction

An ASP file can contain text, HTML tags and scripts. Scripts in an ASP file are executed on the server.

What you should already know

Before you continue you should have some basic understanding of the following:

HTML / XHTML
A scripting language like JavaScript or VBScript

What is ASP?

ASP stands for Active Server Pages
ASP is a Microsoft Technology
ASP is a program that runs inside IIS
IIS stands for Internet Information Services
IIS comes as a free component with Windows 2000
IIS is also a part of the Windows NT 4.0 Option Pack
The Option Pack can be downloaded from Microsoft
PWS is a smaller - but fully functional - version of IIS
PWS can be found on your Windows 95/98 CD

ASP Compatibility

To run IIS you must have Windows NT 4.0 or later
To run PWS you must have Windows 95 or later
ChiliASP is a technology that runs ASP without Windows OS
InstantASP is another technology that runs ASP without Windows

What is an ASP File?

An ASP file is just the same as an HTML file
An ASP file can contain text, HTML, XML, and scripts
Scripts in an ASP file are executed on the server
An ASP file has the file extension ".asp"

How Does ASP Differ from HTML?

When a browser requests an HTML file, the server returns the file
When a browser requests an ASP file, IIS passes the request to the ASP engine. The ASP engine reads the ASP file, line by line, and executes the scripts in the file. Finally, the ASP file is returned to the browser as plain HTML

What can ASP do for you?

Dynamically edit, change, or add any content of a Web page
Respond to user queries or data submitted from HTML forms
Access any data or databases and return the results to a browser
Customize a Web page to make it more useful for individual users
The advantages of using ASP instead of CGI and Perl, are those of simplicity and speed
Provide security - since ASP code cannot be viewed from the browser
Clever ASP programming can minimize the network traffic

Run ASP on Your Own PC

IIS - Internet Information Server

IIS is a set of Internet-based services for servers created by Microsoft for use with Microsoft Windows.

IIS comes with Windows 2000, XP, and Vista. It is also available for Windows NT.

IIS is easy to install and ideal for developing and testing web applications.

Windows Web Server Versions

Windows Vista Business, Enterprise and Ultimate come with IIS 7
Windows Vista Home Premium comes with IIS 7
Windows Vista Home Edition does not support PWS or IIS
Windows XP Professional comes with IIS 5.1
Windows XP Home Edition does not support IIS or PWS
Windows 2000 Professional comes with IIS 5.0
Windows NT Professional comes with IIS 3 and also supports IIS 4
Windows NT Workstation supports PWS and IIS 3
Windows ME does not support PWS or IIS
Windows 98 comes with PWS
Windows 95 supports PWS

How to Install IIS on Windows Vista

Follow these steps to install IIS on Windows Vista:

Open the Control Panel from the Start menu
Double-click Programs and Features
Click "Turn Windows features on or off" (a link to the left)
Select the check box for Internet Information Services (IIS), and click OK

(After you have installed IIS, make Run Windows Update).sure you install all patches for bugs and security problems.

How to Install IIS on Windows XP and Windows 2000

Follow these steps to install IIS on Windows XP and Windows 2000:

On the Start menu, click Settings and select Control Panel
Double-click Add or Remove Programs
Click Add/Remove Windows Components
Click Internet Information Services (IIS)
Click Details
Select the check box for World Wide Web Service, and click OK
In Windows Component selection, click Next to install IIS

After you have installed IIS, make sure you install all patches for bugs and security problems. (Run Windows Update).

Test Your Web

After you have installed IIS or PWS follow these steps:

Look for a new folder called Inetpub on your hard drive
Open the Inetpub folder, and find a folder named wwwroot
Create a new folder, like "MyWeb", under wwwroot
Write some ASP code and save the file as "test1.asp" in the new folder
Make sure your Web server is running (see below)
Open your browser and type "http://localhost/MyWeb/test1.asp", to view your first web page

Note: Look for the IIS (or PWS) symbol in your start menu or task bar. The program has functions for starting and stopping the web server, disable and enable ASP, and much more.

How to install PWS on Windows 95, 98, and Windows NT

For Windows 98: Open the Add-ons folder on your Windows CD, find the PWS folder and run setup.exe to install PWS.

For Windows 95 or Windows NT: Download "Windows NT 4.0 Option Pack" from Microsoft, and install PWS.

Test your web as described above.

ASP Basic Syntax Rules

Write Output to a Browser

An ASP file normally contains HTML tags, just like an HTML file. However, an ASP file can also contain server scripts, surrounded by the delimiters <% and %>.
Server scripts are executed on the server, and can contain any expressions, statements, procedures, or operators valid for the scripting language you prefer to use.

The response.write Command

The response.write command is used to write output to a browser. The following example sends the text "Hello World" to the browser:

Example

There is also a shorthand method for the response.write command. The following example also sends the text "Hello World" to the browser:

Example

Using VBScript in ASP

You can use several scripting languages in ASP. However, the default scripting language is VBScript:

The example above writes "Hello World!" into the body of the document.

Using JavaScript in ASP

To set JavaScript as the default scripting language for a particular page you must insert a language specification at the top of the page:

<%@ language="javascript"%>
<html>
<body>
<%
Response.Write("Hello World!")
%>
</body>
</html>

Note: JavaScript is case sensitive! You will have to write your ASP code with uppercase letters and lowercase letters when the language requires it.

Other Scripting Languages

ASP is shipped with VBScript and JScript (Microsoft's implementation of JavaScript). If you want to script in another language, like PERL, REXX, or Python, you will have to install script engines for them.

ASP Variables

A variable is used to store information.

Try it Yourself - Examples

Declare a variableVariables are used to store information. This example demonstrates how to declare a variable, assign a value to it, and use the value in a text.
<html>
<body>

<%
dim name
name="Donald Duck"
response.write("My name is: " & name)
%>

</body>
</html>

Declare an arrayArrays are used to store a series of related data items. This example demonstrates how to declare an array that stores names.
<html>
<body>

<%
Dim famname(5),i
famname(0) = "Jan Egil"
famname(1) = "Tove"
famname(2) = "Hege"
famname(3) = "Stale"
famname(4) = "Kai Jim"
famname(5) = "Borge"

For i = 0 to 5
      response.write(famname(i) & "<br />")
Next
%>

</body>
</html>
Loop through the HTML headings
How to loop through the six headings in HTML.
<html>
<body>

<%
dim i
for i=1 to 6
   response.write("<h" & i & ">Heading " & i & "</h" & i & ">")
next
%>

</body>
</html>

Time-based greeting using VBScript
This example will display a different message to the user depending on the time on the server.
<html>
<body>
<%
dim h
h=hour(now())

response.write("<p>" & now())
response.write("</p>")
If h<12 then
   response.write("Good Morning!")
else
   response.write("Good day!")
end if
%>
</body>
</html>
Time-based greeting using JavaScript
This example is the same as the one above, but the syntax is different.
<%@ language="javascript" %>
<html>
<body>
<%
var d=new Date()
var h=d.getHours()

Response.Write("<p>")
Response.Write(d)
Response.Write("</p>")
if (h<12)
   {
   Response.Write("Good Morning!")
   }
else
   {
   Response.Write("Good day!")
   }
%>
</body>
</html>

Lifetime of Variables

A variable declared outside a procedure can be accessed and changed by any script in the ASP file.
A variable declared inside a procedure is created and destroyed every time the procedure is executed. No scripts outside the procedure can access or change the variable.
To declare variables accessible to more than one ASP file, declare them as session variables or application variables.

Session Variables

Session variables are used to store information about ONE single user, and are available to all pages in one application. Typically information stored in session variables are name, id, and preferences.

Application Variables

Application variables are also available to all pages in one application. Application variables are used to store information about ALL users in one specific application.

ASP Procedures

In ASP you can call a JavaScript procedure from a VBScript and vice versa.

Procedures

The ASP source code can contain procedures and functions:

Example

<html>
<head>
<%
sub vbproc(num1,num2)
response.write(num1*num2)
end sub
%>
</head>
<body>

<p>Result: <%call vbproc(3,4)%></p>

</body>
</html>

Show example »

Insert the <%@ language="language" %> line above the <html> tag to write the procedure/function in another scripting language:

Example

<%@ language="javascript" %>
<html>
<head>
<%
function jsproc(num1,num2)
{
Response.Write(num1*num2)
}
%>
</head>
<body>

<p>Result: <%jsproc(3,4)%></p>

</body>
</html>

Differences Between VBScript and JavaScript

When calling a VBScript or a JavaScript procedure from an ASP file written in VBScript, you can use the "call" keyword followed by the procedure name. If a procedure requires parameters, the parameter list must be enclosed in parentheses when using the "call" keyword. If you omit the "call" keyword, the parameter list must not be enclosed in parentheses. If the procedure has no parameters, the parentheses are optional.

When calling a JavaScript or a VBScript procedure from an ASP file written in JavaScript, always use parentheses after the procedure name.

ASP Forms and User Input

The Request.QueryString and Request.Form commands are used to retrieve user input from forms.

Try it Yourself - Examples

A form with method="get"
How to interact with the user, with the Request.QueryString command.
<html>
<body>
<form action="demo_reqquery.asp" method="get">
Your name: <input type="text" name="fname" size="20" />
<input type="submit" value="Submit" />
</form>
<%
dim fname
fname=Request.QueryString("fname")
If fname<>"" Then
      Response.Write("Hello " & fname & "!<br />")
      Response.Write("How are you today?")
End If
%>
</body>
</html>
A form with method="post"
How to interact with the user, with the Request.Form command.
<html>
<body>
<form action="demo_simpleform.asp" method="post">
Your name: <input type="text" name="fname" size="20" />
<input type="submit" value="Submit" />
</form>
<%
dim fname
fname=Request.Form("fname")
If fname<>"" Then
      Response.Write("Hello " & fname & "!<br />")
      Response.Write("How are you today?")
End If
%>
</body>
</html>

A form with radio buttonsHow to interact with the user, through radio buttons, with the Request.Form command.
<html>
<%
dim cars
cars=Request.Form("cars")
%>
<body>
<form action="demo_radiob.asp" method="post">
<p>Please select your favorite car:</p>

<input type="radio" name="cars"
<%if cars="Volvo" then Response.Write("checked")%>
value="Volvo">Volvo</input>
<br />
<input type="radio" name="cars"
<%if cars="Saab" then Response.Write("checked")%>
value="Saab">Saab</input>
<br />
<input type="radio" name="cars"
<%if cars="BMW" then Response.Write("checked")%>
value="BMW">BMW</input>
<br /><br />
<input type="submit" value="Submit" />
</form>
<%
if cars<>"" then
   Response.Write("<p>Your favorite car is: " & cars & "</p>")
end if
%>
</body>
</html>

User Input

The Request object can be used to retrieve user information from forms.

Example HTML form

<form method="get" action="simpleform.asp">
First Name: <input type="text" name="fname" /><br />
Last Name: <input type="text" name="lname" /><br /><br />
<input type="submit" value="Submit" />
</form>

User input can be retrieved with the Request.QueryString or Request.Form command.

Request.QueryString

The Request.QueryString command is used to collect values in a form with method="get".
Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has limits on the amount of information to send.
If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:

http://www.w3schools.com/simpleform.asp?fname=Bill&lname=Gates

Assume that "simpleform.asp" contains the following ASP script:

<body>
Welcome
<%
response.write(request.querystring("fname"))
response.write(" " & request.querystring("lname"))
%>
</body>

The browser will display the following in the body of the document:

Welcome Bill Gates

Request.Form

The Request.Form command is used to collect values in a form with method="post".
Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.
If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:

http://www.w3schools.com/simpleform.asp

Assume that "simpleform.asp" contains the following ASP script:

<body>
Welcome
<%
response.write(request.form("fname"))
response.write(" " & request.form("lname"))
%>
</body>

The browser will display the following in the body of the document:

Welcome Bill Gates

Form Validation

User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the server load.
You should consider server validation if the user input will be inserted into a database. A good way to validate a form on the server is to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the form. This makes it easier to discover the error.

ASP Cookies

A cookie is often used to identify a user.

Try it Yourself - Examples

Welcome cookie
How to create a Welcome cookie.
<%
dim numvisits
response.cookies("NumVisits").Expires=date+365
numvisits=request.cookies("NumVisits")

if numvisits="" then
   response.cookies("NumVisits")=1
   response.write("Welcome! This is the first time you are visiting this Web page.")
else
   response.cookies("NumVisits")=numvisits+1
   response.write("You have visited this ")
   response.write("Web page " & numvisits)
   if numvisits=1 then
     response.write " time before!"
   else
     response.write " times before!"
   end if
end if
%>
<html>
<body>
</body>
</ht

What is a Cookie?

A cookie is often used to identify a user. A cookie is a small file that the server embeds on the user's computer. Each time the same computer requests a page with a browser, it will send the cookie too. With ASP, you can both create and retrieve cookie values.

How to Create a Cookie?

The "Response.Cookies" command is used to create cookies.
Note: The Response.Cookies command must appear BEFORE the <html> tag.
In the example below, we will create a cookie named "firstname" and assign the value "Alex" to it:

<%
Response.Cookies("firstname")="Alex"
%>

It is also possible to assign properties to a cookie, like setting a date when the cookie should expire:

<%
Response.Cookies("firstname")="Alex"
Response.Cookies("firstname").Expires=#May 10,2012#
%>

How to Retrieve a Cookie Value?

The "Request.Cookies" command is used to retrieve a cookie value.
In the example below, we retrieve the value of the cookie named "firstname" and display it on a page:

<%
fname=Request.Cookies("firstname")
response.write("Firstname=" & fname)
%>

Output: Firstname=Alex

A Cookie with Keys

If a cookie contains a collection of multiple values, we say that the cookie has Keys.
In the example below, we will create a cookie collection named "user". The "user" cookie has Keys that contains information about a user:

<%
Response.Cookies("user")("firstname")="John"
Response.Cookies("user")("lastname")="Smith"
Response.Cookies("user")("country")="Norway"
Response.Cookies("user")("age")="25"
%>

Read all Cookies

Look at the following code:

<%
Response.Cookies("firstname")="Alex"
Response.Cookies("user")("firstname")="John"
Response.Cookies("user")("lastname")="Smith"
Response.Cookies("user")("country")="Norway"
Response.Cookies("user")("age")="25"
%>

Assume that your server has sent all the cookies above to a user.
Now we want to read all the cookies sent to a user. The example below shows how to do it (note that the code below checks if a cookie has Keys with the HasKeys property):

<html>
<body>

<%
dim x,y
for each x in Request.Cookies
response.write("<p>")
if Request.Cookies(x).HasKeys then
    for each y in Request.Cookies(x)
      response.write(x & ":" & y & "=" & Request.Cookies(x)(y))
      response.write("<br />")
    next
else
    Response.Write(x & "=" & Request.Cookies(x) & "<br />")
end if
response.write "</p>"
next
%>

</body>
</html>

Output:
firstname=Alex
user:firstname=John
user:lastname=Smith
user:country=Norway
user:age=25

What if a Browser Does NOT Support Cookies?

If your application deals with browsers that do not support cookies, you will have to use other methods to pass information from one page to another in your application. There are two ways of doing this:

1. Add parameters to a URL

You can add parameters to a URL:

<a href="welcome.asp?fname=John&lname=Smith">Go to Welcome Page</a>

And retrieve the values in the "welcome.asp" file like this:

<%
fname=Request.querystring("fname")
lname=Request.querystring("lname")
response.write("<p>Hello " & fname & " " & lname & "!</p>")
response.write("<p>Welcome to my Web site!</p>")
%>

2. Use a form

You can use a form. The form passes the user input to "welcome.asp" when the user clicks on the Submit button:

<form method="post" action="welcome.asp">
First Name: <input type="text" name="fname" value="" />
Last Name: <input type="text" name="lname" value="" />
<input type="submit" value="Submit" />
</form>

Retrieve the values in the "welcome.asp" file like this:

<%
fname=Request.form("fname")
lname=Request.form("lname")
response.write("<p>Hello " & fname & " " & lname & "!</p>")
response.write("<p>Welcome to my Web site!</p>")
%>

ASP Session Object

A Session object stores information about, or change settings for a user session.

The Session object

When you are working with an application on your computer, you open it, do some changes and then you close it. This is much like a Session. The computer knows who you are. It knows when you open the application and when you close it. However, on the internet there is one problem: the web server does not know who you are and what you do, because the HTTP address doesn't maintain state.

ASP solves this problem by creating a unique cookie for each user. The cookie is sent to the user's computer and it contains information that identifies the user. This interface is called the Session object.

The Session object stores information about, or change settings for a user session.

Variables stored in a Session object hold information about one single user, and are available to all pages in one application. Common information stored in session variables are name, id, and preferences. The server creates a new Session object for each new user, and destroys the Session object when the session expires.

When does a Session Start?

A session starts when:

A new user requests an ASP file, and the Global.asa file includes a Session_OnStart procedure
A value is stored in a Session variable
A user requests an ASP file, and the Global.asa file uses the <object> tag to instantiate an object with session scope

When does a Session End?

A session ends if a user has not requested or refreshed a page in the application for a specified period. By default, this is 20 minutes.

If you want to set a timeout interval that is shorter or longer than the default, use the Timeout property.

The example below sets a timeout interval of 5 minutes:

<%
Session.Timeout=5
%>

Use the Abandon method to end a session immediately:

<%
Session.Abandon
%>

Note: The main problem with sessions is WHEN they should end. We do not know if the user's last request was the final one or not. So we do not know how long we should keep the session "alive". Waiting too long for an idle session uses up resources on the server, but if the session is deleted too soon the user has to start all over again because the server has deleted all the information. Finding the right timeout interval can be difficult!

Tip: Only store SMALL amounts of data in session variables!

Store and Retrieve Session Variables

The most important thing about the Session object is that you can store variables in it.

The example below will set the Session variable username to "Donald Duck" and the Session variable age to "50":

<%
Session("username")="Donald Duck"
Session("age")=50
%>

When the value is stored in a session variable it can be reached from ANY page in the ASP application:

Welcome <%Response.Write(Session("username"))%>

The line above returns: "Welcome Donald Duck".

You can also store user preferences in the Session object, and then access that preference to choose what page to return to the user.

The example below specifies a text-only version of the page if the user has a low screen resolution:

<%If Session("screenres")="low" Then%>
This is the text version of the page
<%Else%>
This is the multimedia version of the page
<%End If%>

Remove Session Variables

The Contents collection contains all session variables.

It is possible to remove a session variable with the Remove method.

The example below removes the session variable "sale" if the value of the session variable "age" is lower than 18:

<%
If Session.Contents("age")<18 then
Session.Contents.Remove("sale")
End If
%>

To remove all variables in a session, use the RemoveAll method:

<%
Session.Contents.RemoveAll()
%>

Loop Through the Contents Collection

The Contents collection contains all session variables. You can loop through the Contents collection, to see what's stored in it:

<%
Session("username")="Donald Duck"
Session("age")=50

dim i
For Each i in Session.Contents
Response.Write(i & "<br />")
Next
%>

Result:

username
age

If you do not know the number of items in the Contents collection, you can use the Count property:

<%
dim i
dim j
j=Session.Contents.Count
Response.Write("Session variables: " & j)
For i=1 to j
Response.Write(Session.Contents(i) & "<br />")
Next
%>

Result:

Session variables: 2
Donald Duck
50

Loop Through the StaticObjects Collection

You can loop through the StaticObjects collection, to see the values of all objects stored in the Session object:

<%
dim i
For Each i in Session.StaticObjects
Response.Write(i & "<br />")
Next
%>

ASP Application Object

A group of ASP files that work together to perform some purpose is called an application.

Application Object

An application on the Web may consists of several ASP files that work together to perform some purpose. The Application object is used to tie these files together.

The Application object is used to store and access variables from any page, just like the Session object. The difference is that ALL users share ONE Application object (with Sessions there is ONE Session object for EACH user).

The Application object holds information that will be used by many pages in the application (like database connection information). The information can be accessed from any page. The information can also be changed in one place, and the changes will automatically be reflected on all pages.

Store and Retrieve Application Variables

Application variables can be accessed and changed by any page in an application.

You can create Application variables in "Global.asa" like this:

In the example above we have created two Application variables: "vartime" and "users".

You can access the value of an Application variable like this:

There are
<%
Response.Write(Application("users"))
%>
active connections.

Loop Through the Contents Collection

The Contents collection contains all application variables. You can loop through the Contents collection, to see what's stored in it:

<%
dim i
For Each i in Application.Contents
Response.Write(i & "<br />")
Next
%>

If you do not know the number of items in the Contents collection, you can use the Count property:

<%
dim i
dim j
j=Application.Contents.Count
For i=1 to j
Response.Write(Application.Contents(i) & "<br />")
Next
%>

Loop Through the StaticObjects Collection

You can loop through the StaticObjects collection, to see the values of all objects stored in the Application object:

<%
dim i
For Each i in Application.StaticObjects
Response.Write(i & "<br />")
Next
%>

Lock and Unlock

You can lock an application with the "Lock" method. When an application is locked, the users cannot change the Application variables (other than the one currently accessing it). You can unlock an application with the "Unlock" method. This method removes the lock from the Application variable:

<%
Application.Lock
'do some application object operations
Application.Unlock
%>

ASP Including Files

The #include Directive

You can insert the content of one ASP file into another ASP file before the server executes it, with the #include directive.
The #include directive is used to create functions, headers, footers, or elements that will be reused on multiple pages.

How to Use the #include Directive

Here is a file called "mypage.asp":

<html>
<body>
<h3>Words of Wisdom:</h3>
<p></p>
<h3>The time is:</h3>
<p></p>
</body>
</html>

Here is the "wisdom.inc" file:

"One should never increase, beyond what is necessary,
the number of entities required to explain anything."

Here is the "time.inc" file:

<%
Response.Write(Time)
%>

If you look at the source code in a browser, it will look something like this:

<html>
<body>
<h3>Words of Wisdom:</h3>
<p>"One should never increase, beyond what is necessary,
the number of entities required to explain anything."</p>
<h3>The time is:</h3>
<p>11:33:42 AM</p>
</body>
</html>

Syntax for Including Files

To include a file in an ASP page, place the #include directive inside comment tags:

or

The Virtual Keyword

Use the virtual keyword to indicate a path beginning with a virtual directory.
If a file named "header.inc" resides in a virtual directory named /html, the following line would insert the contents of "header.inc":

The File Keyword

Use the file keyword to indicate a relative path. A relative path begins with the directory that contains the including file.
If you have a file in the html directory, and the file "header.inc" resides in html\headers, the following line would insert "header.inc" in your file:

Note that the path to the included file (headers\header.inc) is relative to the including file. If the file containing this #include statement is not in the html directory, the statement will not work.

Tips and Notes

In the sections above we have used the file extension ".inc" for included files. Notice that if a user tries to browse an INC file directly, its content will be displayed. If your included file contains confidential information or information you do not want any users to see, it is better to use an ASP extension. The source code in an ASP file will not be visible after the interpretation. An included file can also include other files, and one ASP file can include the same file more than once.

Important: Included files are processed and inserted before the scripts are executed. The following script will NOT work because ASP executes the #include directive before it assigns a value to the variable:

<%
fname="header.inc"
%>

You cannot open or close a script delimiter in an INC file. The following script will NOT work:

<%
For i = 1 To n

Next
%>

But this script will work:

<% For i = 1 to n %>

<% Next %>

ASP Including Files

The #include Directive

Syntax for Including Files

To include a file in an ASP page, place the #include directive inside comment tags:

or

The Virtual Keyword

The File Keyword

Tips and Notes

<%
fname="header.inc"
%>

You cannot open or close a script delimiter in an INC file. The following script will NOT work:

<%
For i = 1 To n

Next
%>

But this script will work:

<% For i = 1 to n %>

<% Next %>

ASP The Global.asa file

The Global.asa file

The Global.asa file is an optional file that can contain declarations of objects, variables, and methods that can be accessed by every page in an ASP application.
All valid browser scripts (JavaScript, VBScript, JScript, PerlScript, etc.) can be used within Global.asa.
The Global.asa file can contain only the following:

Application events
Session events
<object> declarations
TypeLibrary declarations
the #include directive

Note: The Global.asa file must be stored in the root directory of the ASP application, and each application can only have one Global.asa file.

Events in Global.asa

In Global.asa you can tell the application and session objects what to do when the application/session starts and what to do when the application/session ends. The code for this is placed in event handlers. The Global.asa file can contain four types of events:

Application_OnStart - Occurs when the FIRST user calls the first page in an ASP application. This event occurs after the Web server is restarted or after the Global.asa file is edited. The "Session_OnStart" event occurs immediately after this event.

Session_OnStart - This event occurs EVERY time a NEW user requests his or her first page in the ASP application.
Session_OnEnd - This event occurs EVERY time a user ends a session. A user-session ends after a page has not been requested by the user for a specified time (by default this is 20 minutes).
Application_OnEnd - This event occurs after the LAST user has ended the session. Typically, this event occurs when a Web server stops. This procedure is used to clean up settings after the Application stops, like delete records or write information to text files.
A Global.asa file could look something like this:

Note: Because we cannot use the ASP script delimiters (<% and %>) to insert scripts in the Global.asa file, we put subroutines inside an HTML <script> element.

<object> Declarations

It is possible to create objects with session or application scope in Global.asa by using the <object> tag.
Note: The <object> tag should be outside the <script> tag!

Syntax

Parameter	Description
scope	Sets the scope of the object (either Session or Application)
id	Specifies a unique id for the object
ProgID	An id associated with a class id. The format for ProgID is [Vendor.]Component[.Version] Either ProgID or ClassID must be specified.
ClassID	Specifies a unique id for a COM class object. Either ProgID or ClassID must be specified.

Examples

The first example creates an object of session scope named "MyAd" by using the ProgID parameter:

The second example creates an object of application scope named "MyConnection" by using the ClassID parameter:

The objects declared in the Global.asa file can be used by any script in the application:

GLOBAL.ASA:

<object runat="server" scope="session" id="MyAd" progid="MSWC.AdRotator">
</object>

You could reference the object "MyAd" from any page in the ASP application:

SOME .ASP FILE:

<%=MyAd.GetAdvertisement("/banners/adrot.txt")%>

TypeLibrary Declarations

A TypeLibrary is a container for the contents of a DLL file corresponding to a COM object. By including a call to the TypeLibrary in the Global.asa file, the constants of the COM object can be accessed, and errors can be better reported by the ASP code. If your Web application relies on COM objects that have declared data types in type libraries, you can declare the type libraries in Global.asa.

Syntax

Parameter	Description
file	Specifies an absolute path to a type library. Either the file parameter or the uuid parameter is required
uuid	Specifies a unique identifier for the type library. Either the file parameter or the uuid parameter is required
version	Optional. Used for selecting version. If the requested version is not found, then the most recent version is used
lcid	Optional. The locale identifier to be used for the type library

Error Values

The server can return one of the following error messages:

Error Code	Description
ASP 0222	Invalid type library specification
ASP 0223	Type library not found
ASP 0224	Type library cannot be loaded
ASP 0225	Type library cannot be wrapped

Note: METADATA tags can appear anywhere in the Global.asa file (both inside and outside <script> tags). However, it is recommended that METADATA tags appear near the top of the Global.asa file.

Restrictions

Restrictions on what you can include in the Global.asa file:

You cannot display text written in the Global.asa file. This file can't display information
You can only use Server and Application objects in the Application_OnStart and Application_OnEnd subroutines. In the Session_OnEnd subroutine, you can use Server, Application, and Session objects. In the Session_OnStart subroutine you can use any built-in object

How to use the Subroutines

Global.asa is often used to initialize variables.

The example below shows how to detect the exact time a visitor first arrives on a Web site. The time is stored in a Session variable named "started", and the value of the "started" variable can be accessed from any ASP page in the application:

Global.asa can also be used to control page access.
The example below shows how to redirect every new visitor to another page, in this case to a page called "newpage.asp":

And you can include functions in the Global.asa file.
In the example below the Application_OnStart subroutine occurs when the Web server starts. Then the Application_OnStart subroutine calls another subroutine named "getcustomers". The "getcustomers" subroutine opens a database and retrieves a record set from the "customers" table. The record set is assigned to an array, where it can be accessed from any ASP page without querying the database:

Global.asa Example

In this example we will create a Global.asa file that counts the number of current visitors.

The Application_OnStart sets the Application variable "visitors" to 0 when the server starts
The Session_OnStart subroutine adds one to the variable "visitors" every time a new visitor arrives
The Session_OnEnd subroutine subtracts one from "visitors" each time this subroutine is triggered

The Global.asa file:

To display the number of current visitors in an ASP file:

<html>
<head>
</head>
<body>
<p>There are <%response.write(Application("visitors"))%> online now!</p>
</body>
</html>

ASP Sending e-mail with CDOSYS

CDOSYS is a built-in component in ASP. This component is used to send e-mails with ASP.

Sending e-mail with CDOSYS

CDO (Collaboration Data Objects) is a Microsoft technology that is designed to simplify the creation of messaging applications.

CDOSYS is a built-in component in ASP. We will show you how to use this component to send e-mail with ASP.

How about CDONTs?

Microsoft has discontinued the use of CDONTs on Windows 2000, Windows XP and Windows 2003. If you have used CDONTs in your ASP applications, you should update the code and use the new CDO technology.

Examples using CDOSYS

Sending a text e-mail:

Sending a text e-mail with Bcc and CC fields:

<%
Set myMail=CreateObject("CDO.Message")
myMail.Subject="Sending email with CDO"
myMail.From="mymail@mydomain.com"
myMail.To="someone@somedomain.com"
myMail.Bcc="someoneelse@somedomain.com"
myMail.Cc="someoneelse2@somedomain.com"
myMail.TextBody="This is a message."
myMail.Send
set myMail=nothing
%>

Sending an HTML e-mail:

<%
Set myMail=CreateObject("CDO.Message")
myMail.Subject="Sending email with CDO"
myMail.From="mymail@mydomain.com"
myMail.To="someone@somedomain.com"
myMail.HTMLBody = "<h1>This is a message.</h1>"
myMail.Send
set myMail=nothing
%>

Sending an HTML e-mail that sends a webpage from a website:

<%
Set myMail=CreateObject("CDO.Message")
myMail.Subject="Sending email with CDO"
myMail.From="mymail@mydomain.com"
myMail.To="someone@somedomain.com"
myMail.CreateMHTMLBody "http://www.w3schools.com/asp/"
myMail.Send
set myMail=nothing
%>

Sending an HTML e-mail that sends a webpage from a file on your computer:

<%
Set myMail=CreateObject("CDO.Message")
myMail.Subject="Sending email with CDO"
myMail.From="mymail@mydomain.com"
myMail.To="someone@somedomain.com"
myMail.CreateMHTMLBody "file://c:/mydocuments/test.htm"
myMail.Send
set myMail=nothing
%>

Sending a text e-mail with an Attachment:

Sending a text e-mail using a remote server:

<%
Set myMail=CreateObject("CDO.Message")
myMail.Subject="Sending email with CDO"
myMail.From="mymail@mydomain.com"
myMail.To="someone@somedomain.com"
myMail.TextBody="This is a message."
myMail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/sendusing")=2
'Name or IP of remote SMTP server
myMail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserver")="smtp.server.com"
'Server port
myMail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserverport")=25
myMail.Configuration.Fields.Update
myMail.Send
set myMail=nothing
%>

ASP Response Object

The ASP Response object is used to send output to the user from the server.

Try it Yourself – Examples

Write text with ASP
How to write text with ASP.
<html>
<body>

<%
response.write("Hello World!")
%>

</body>
</html>

Format text with HTML tags in ASP
How to combine text and HTML tags with ASP.
<html>
<body>
<%
response.write("<h2>You can use HTML tags to format the text!</h2>")
%>

<%
response.write("<p style='color:#0000ff'>This text is styled with the style attribute!</p>")
%>
</body>
</html>
Redirect the user to a different URL
How to redirect the user to a different URL.
<html>
<body>

<%
randomize()
r=rnd()
if r>0.5 then
response.write("<a href='http://www.w3schools.com'>W3Schools.com!</a>")
else
response.write("<a href='http://www.refsnesdata.no'>Refsnesdata.no!</a>")
end if
%>

<p>
This example demonstrates a link, each time you load the page, it will display
one of two links: W3Schools.com! OR Refsnesdata.no! There is a 50% chance for
each of them.
</p>

</body>
</html>

Show a random link
How to create a random link.
<%
Response.Buffer=true
%>
<html>
<body>
<p>
This text will be sent to your browser when my response buffer is flushed.
</p>
<%
Response.Flush
%>
</body>
</html>
Controlling the buffer
How to control the buffer.
<%
Response.Buffer=true
%>
<html>
<body>
<p>This is some text I want to send to the user.</p>
<p>No, I changed my mind. I want to clear the text.</p>
<%
Response.Clear
%>
</body>
</html>
Clear the buffer
How to clear the buffer.
<%
Response.Buffer=true
%>
<html>
<body>
<p>
This text will be sent to your browser when my response buffer is flushed.
</p>
<%
Response.Flush
%>
</body>
</html>

End a script in the middle of processing and return the result
How to end a script in the middle of processing.
<html>
<body>
<p>I am writing some text. This text will never be<br />
<%
Response.End
%>
finished! It's too late to write more!</p>
</body>
</html>
Set how many minutes a page will be cached in a browser before it expires
How to specify how many minutes a page will be cached in a browser before it expires.
<%Response.Expires=-1%>
<html>
<body>
<p>This page will be refreshed with each access!</p>
</body>
</html>
Set a date/time when a page cached in a browser will expire
How to specify a date/time a page cached in a browser will expire.
<%
Response.ExpiresAbsolute=#May 05,2001 05:30:30#
%>
<html>
<body>
<p>This page will expire on May 05, 2001 05:30:30!</p>
</body>
</html>
Check if the user is still connected to the server
How to check if a user is disconnected from the server.
<html>
<body>

<%
If Response.IsClientConnected=true then
Response.Write("The user is still connected!")
else
Response.Write("The user is not connected!")
end if
%>

</body>
</html>
Set the type of content
How to specify the type of content.
<%
Response.ContentType="text/html"
%>
<html>
<body>

<p>This is some text</p>

</body>
</html>
Set the name of the character set
How to specify the name of the character set.
<%
Response.Charset="ISO8859-1"
%>
<html>
<body>

<p>This is some text</p>

</body>
</html>

Response Object

The ASP Response object is used to send output to the user from the server. Its collections, properties, and methods are described below:

Collections

Collection	Description
Cookies	Sets a cookie value. If the cookie does not exist, it will be created, and take the value that is specified

Properties

Property	Description
Buffer	Specifies whether to buffer the page output or not
CacheControl	Sets whether a proxy server can cache the output generated by ASP or not
Charset	Appends the name of a character-set to the content-type header in the Response object
ContentType	Sets the HTTP content type for the Response object
Expires	Sets how long (in minutes) a page will be cached on a browser before it expires
ExpiresAbsolute	Sets a date and time when a page cached on a browser will expire
IsClientConnected	Indicates if the client has disconnected from the server
Pics	Appends a value to the PICS label response header
Status	Specifies the value of the status line returned by the server

Methods

Method	Description
AddHeader	Adds a new HTTP header and a value to the HTTP response
AppendToLog	Adds a string to the end of the server log entry
BinaryWrite	Writes data directly to the output without any character conversion
Clear	Clears any buffered HTML output
End	Stops processing a script, and returns the current result
Flush	Sends buffered HTML output immediately
Redirect	Redirects the user to a different URL
Write	Writes a specified string to the output

ASP ( ActiveX Server Pages ) Notes For BCA & MCA

ASP Basic Syntax Rules

Write Output to a Browser

The response.write Command

Example

Example

Using JavaScript in ASP

Other Scripting Languages

ASP Variables

Try it Yourself - Examples

Lifetime of Variables

Session Variables

Application Variables

ASP Forms and User Input

Try it Yourself - Examples

User Input

Example HTML form

Request.QueryString

Request.Form

Form Validation

ASP Cookies

Try it Yourself - Examples

What is a Cookie?

How to Create a Cookie?

How to Retrieve a Cookie Value?

A Cookie with Keys

Read all Cookies

What if a Browser Does NOT Support Cookies?

1. Add parameters to a URL

2. Use a form

ASP Including Files

The #include Directive

How to Use the #include Directive

Syntax for Including Files

The Virtual Keyword

The File Keyword

Tips and Notes

ASP Including Files

The #include Directive

Syntax for Including Files

The Virtual Keyword

The File Keyword

Tips and Notes

ASP The Global.asa file

The Global.asa file

Events in Global.asa

<object> Declarations

Syntax

Examples

TypeLibrary Declarations

Syntax

Error Values

Restrictions

How to use the Subroutines

Global.asa is often used to initialize variables.

Global.asa Example

ASP Response Object

Try it Yourself – Examples

Response Object

Collections

Properties

Methods

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