How to extract content from source generated by javascript

I need to extract content generated with javascript from a site. I cannot extract the data considering the source because the content in the page itself looks like this:

<script type="text/javascript" src="java1.js"></script>
<script type="text/javascript" src="java2.js"></script>

The content generated with those java1.js and java2.js so I need to extract the HTML source generated with these js 开发者_StackOverflow社区scripts.

I can extract the content manually using Firefox by selecting the contents then right click then chose "view selection source", but I am looking for an automated solution with perl, python or whatever language that would be able to do this.

Win32::IE::Mechanize