[Greasemonkey] getting all of web page into a string

[Al]

Can you use GM javascript to pull the entire contents of a web page, 
on which the script is running, into a string?

I'd like to use regular expressions to check if the page I'm running on contains
a phrase.  I think I can do it the hard way with getElementByTagName("*"), 
but then i have to check for all the children.

thanks,
Al