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

Script

javascript:document.open('text/html');document.write('
OMG HAI2U!!!1
');document.close();

DOM snapshot of the resulting page

OMG HAI2U!!!1