Which browsers support document.activeElement?
Which web browsers / versions have support for document.activeElement?
This property lets you see which element is active / has focus.
Are there any main gotchas/difference between implementations?
document.activeElement is supported by IE6+, FF3+, Safari 4+, Opera 9+, Chrome 9+. (FF2, Saf3 don't support this property)
It still doesn't work on WebKit based browsers in xhtml page see https://bugs.webkit.org/show_bug.cgi?id=63922