I was able to find the browser object references for Firefox and IE...
Firefox: https://developer.mozilla.org/en/Gecko_DOM_Reference
IE: http://msdn.microsoft.com/en-us/library/ms533054(VS.85).aspx
But, I am unable to find the object references for the other popular browsers. I assume that Safari and Chrome have a similar object structure (since they are both based on the WebKit engine). I also assume that Opera generally uses properties defined by Firefox/IE (just to be compatible with those browsers)...
Do those browsers have object references somewhere online?