【读书笔记】 网页关闭确认框

关键部分用粗黑体。
function goodbye(e) {
	if(!e) e = window.event;
	//e.cancelBubble is supported by IE - this will kill the bubbling process.
	e.cancelBubble = true;
	e.returnValue = 'You sure you want to leave?'; //This is displayed on the dialog

	//e.stopPropagation works in Firefox.
	if (e.stopPropagation) {
		e.stopPropagation();
		e.preventDefault();
	}
}
window.onbeforeunload=goodbye;