javascript捕获浏览器窗口关闭事件

为了防止用户不小心关闭浏览器窗口，或者我们想在浏览器窗口关闭的时候做一些事，那么我们会使用到window对象的onbeforeunload和onunload。

<script type="text/javascript">

showValue();

window.onbeforeunload = onbeforeunload_handler;
window.onunload = onunload_handler;

function onbeforeunload_handler(){
return "Are sure to leave?"
}

function onunload_handler(){
storeValue("hehehe");
}

function showValue()
{
var localStorage = window.localStorage;
alert(localStorage.getItem("key"));
}

function storeValue(value)
{
var localStorage = window.localStorage;
localStorage.setItem("key",value);
}

</script>