Determine the browser rendering mode JavaScript

The determine the current rendering mode paste this javascript in the address bar and execute it. It will display the rendering mode of the current site and any embedded frames. It should work on any browser.

javascript:void((function(){var i=0,s='',w=window,m='Main page: '+document.compatMode+'\n\nFrames:\n',f;while(f=window.frames[i]){s+=' '+(f.name?f.name:'Anonymous frame')+': '+f.document.compatMode +'\n';i++;}s=(s?s:'No frames');alert(m+s);})())