In IE8 Quirk Mode (without good doctype), CSS properties are reset when they aren't understood. In IE8 Standards, they are discarted.

background-color: rgb(10,10,10);
background-color: rgba(10,10,10,0.5);

In this example, IE8 Quirk Mode doesn't understand rgba() and reset the background-color to white. In IE8 Standards, the background is rgb(10,10,10) (the first instruction understood).


Methods/attributes SPEC MOZ MSIE8 MSIE9
event.stopPropagation() DOM3 Events OK no: window.event.cancelBubble = true OK
HTMLElement.addEventListener(type,listener,useCapture) DOM2 Events OK no: HTMLElement.attachEvent('on'+type, listener) OK