An Introduction to ASP
What is ASP?
Active Server Pages is a programming environment that
gives the ability to generate dynamic html pages with the help of server side scripting.
VBScript is the default scripting language for ASP, but if you like you can use
VBScript, JScript, Perl or any other scripting language for server side scripting
in an ASP page. An ASP page is almost the same as a HTM or HTML page... the only
difference is that an ASP page has the '.asp' extension. Active Server Page can
include both client side and server side scripts. In an ASP page VBScript is usually
used as the server side and Java Script as the client side scripting language.
Do i need any special software to write ASP?
You don't need any special software to write an ASP page.
An ASP page can be written with any HTML editor... even in Windows Notepad. If you
are looking for some special software to write an ASP page, Microsoft Visual InterDev
is the best tool for you. InterDev helps you to easily develop ASP applications
because it simplifies the process of developing and debugging ASP applications.
Browser independent.
ASP is browser independent because all the scripting code
runs on the server and the browser only gets a normal HTML page as a result of server
side scripting.
How ASP work?
In Case of a HTM or HTML page.
• A user requests a web page in the browser (i.e., 'http://www.devasp.com/test.htm')
• Browser requests the required page from the server (like IIS or
PWS).
• Server reads the required file from memory or the file system
and sends it back to the Browser.
• Browser executes the client side scripting (i.e., Java scripts)
and displays the results.
In case of Active Server Page.
• A user requests a web page in the browser with a file extension
.asp
(i.e., 'http://www.devasp.com/test.asp')
• Browser requests the page from the server (like IIS or PWS).
• Server reads the required file from memory or the file system
and recognizes that the file has
an '.asp' extension.
• Server sends that file to ASP.dll.
• ASP.dll reads the file with the '.asp' extension from top to bottom
and executes all the codes
within the <% and
%> tags and produces a standard HTML page.
• The server sends that HTML page back to browser.
• Browser executes the client side scripting (i.e., Java scripts)
and displays the results to the
user in the browser window.
Let us take a look at this simple ASP example to get a better idea how ASP works.
File: HelloWorld.asp
<head>
<title>Hello World</title>
</head>
<body>
<h2>
My First ASP Page.</h2>
<% For I = 1 To 5 %>
<font size="<%=I%>">Hello World </font>
<br>
<% Next %>
</body>
</html>
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If you request this page in browser this is the result
what you will see in the browser as output of this page.
Now if you check "View Source" behind this page you will see
something like this.
What happend actually when you requests this page in web browser.
Server reads the file extension and recognize that this is an ASP file and need
to execute before send back to browser. ASP.dll reads the file from top to bottom
and the executes the code written in between <% and
%> tags and browser only gets a result of that server
side scripting.
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