Most web browsers allow you to right-click a webpage, and "View Source". But what many people don't understand is that what you are actually viewing is only what was "served" to your client-computer, and NOT the original source-code stored on the server.

For example...

Lets's say you are viewing a document in a server-side scripting language (such as Perl, ASP, or PHP). The server will execute (run) the script, and then serve the script's output to the client computer. So what the client computer recieves is NOT the original server-side script source, but the output (object) produced by the execution of the script. In other words, the server's object code is the client's source code.

So then when you right click the page and hit "View Source", you won't be viewing the original Perl, ASP, PHP, etc. source code! Instead, you'll be view the HTML output generated by that script.

JasonsJungle.com is written in PHP. But if you "View Source" on any page in JasonsJungle.com, you won't see an iota of PHP source code, because all the PHP source was executed on the server. So only the HTML generated by the PHP's execution is available for your viewing.

However, if the page contains a client-side script (such as Javascript or VBScript) and you hit "View Source", you actually will see the script's source code. This is because the script is not executed by the server. It is served to the client to be executed there.

Related Articles:

What's the difference in Javascript & VBscript?
A little education on client-side scripting languages

Server-side vs. Client-side
What does it mean?

Server-side and Client-Side scripting languages
What exactly is going on?