Replacing Entire Page Including Head Using Javascript

Question

I have a Javascript function that is passed a string. The string that it is passed is an entire webpage, including the header. I need the Javascript to replace the entire

Answer 1

var script = document.createElement('script');
script.src = 'http://code.jquery.com/jquery-1.7.2.min.js';
script.type = 'text/javascript';
document.getElementsByTagName('head')[0].appendChild(script);