https://developer.mozilla.org/en/DOM/Manipulating_the_browser_history http://code.google.com/p/chromium/issues/detail?id=101137&q=pushstate&colspec=ID%20Pri%20Mstone%20ReleaseBlock%20Area%20Feature%20Status%20Owner%20Summary

About to run a script - check your browser address field..

NB: Firefox 14 reports "SecurityError: The operation is insecure" if the URL is something like 'http://www.google.com' - I'm guessing it's a cross domain thing. Pretty sure it didn't complain when I first wrote this.

pushState replaceState