Window Active Status

windowstatus.js

function windowVisibility() {
	var v = 'visible', hidden = h = 'hidden', map = {focus:v, focusin:v, pageshow:v, blur:h, focusout:h, pagehide:h};
	if (hidden in D) D.addEventListener("visibilitychange", onchange);
	else if ((hidden = "mozHidden") in D) D.addEventListener("mozvisibilitychange", onchange);
	else if ((hidden = "webkitHidden") in D) D.addEventListener("webkitvisibilitychange", onchange);
	else if ((hidden = "msHidden") in D) D.addEventListener("msvisibilitychange", onchange);
	else if ('onfocusin' in D) D.onfocusin = D.onfocusout = onchange;
	W.onpageshow = W.onpagehide = W.onfocus = W.onblur = onchange;
	function onchange(e) {
		e = e || W.event;
		W.active = ((e.type in map)?map[e.type]:this[hidden]?h:v) == v;
	}
};