Page Visibility API visibility test using jQuery

visibility.js

var isVisible = false;
function onVisible() {
	isVisible = true;
	jQuery.getScript("http://www.google-analytics.com/ga.js");
}

if ( document.webkitVisibilityState === undefined || document.webkitVisibilityState === "visible" ) {
	onVisible();
} else {
	jQuery.bind( "webkitvisibilitychange", function() {
		if ( !isVisible && document.webkitVisibilityState === "visible" ) {
			onVisible();
		}
	});
}