Check whether some element is “focused” without jQuery

问题

I was almost sure I could find the answer here, but I wasn't successful. How would you check whether is there some object selected (focused) on the moment of the event call? I tried if (document.activeElement == "[object HTMLBodyElement]"), but apparently the .activeElement is being filled onLoad. I am not allowed to use jQuery, only mootools.

Thanks a lot for the help!

回答1:

https://developer.mozilla.org/en/DOM/document.activeElement - as pointed out, if no element is focused, the document body is focused by default:

if (document.activeElement != document.body) {
  // something else than the body is focused
}

回答2:

if ( document.body === document.activeElement ) {
  // the body is focused, ie no other element is focused
}

来源：https://stackoverflow.com/questions/7052600/check-whether-some-element-is-focused-without-jquery