How do you specialise the WebRequest and WebResponse to show the content after it is processed by the browser?

Question

I wrote a C# program that uses WebRequest and WebResponse to perform a simple web crawler.  I discovered something about web sites.  Web browsers such as IE and FireFox offer the capacity to view the HTML source code.  But it seems that html code that is sent to the browser is one thing and what the browser interprets and displays is something else.  For example, if you run a google search in IE and run the same google search in FireFox, the content that you can see when you view the source in IE will NOT have the hyperlinks and content from the search results, but you can see the html hyperlinks and content from the search results when you view the source in FireFox.  So my question is this.  How do you specialise the WebRequest and WebResponse to show the content after it is processed by the browser instead of before?