What Layout engine do the common Web Browsers use?
IE
IE uses Trident layout engine. http://en.wikipedia.org/wiki/Trident_(layout_engine)
FireFox
FireFox uses the GECKO layout engine http://www-archive.mozilla.org/newlayout/doc/layout-2006-12-14/master.xhtml https://wiki.mozilla.org/Gecko:Home_Page
Opera
Opera uses the Presto Engine http://www.opera.com/docs/specs/presto29/
Safari
Safari uses the Webkit Layout Engine http://www.webkit.org/
Chrome
Chrome uses the Webkit Layout Engine http://www.google.com/chrome/intl/en/webmasters-faq.html