1,页面加载后 window.onload=function(){};
2,页面(关闭)卸载后触发 window.onunload=function(){};
3,页面关闭前触发 window.onbeforeunload=function(){};
例子:页面刷新
<input type="button" name="name" value="刷新" id="btn" /> <script type="text/javascript"> window.onload = function () { document.getElementById('btn').onclick = function () { window.location.reload(); }; }; </script>