关闭浏览器前给出提示 确认关闭

<script type="text/javascript">
function window.onbeforeunload()
   {
          if(event.clientX>360&&event.clientY<0)
          {
                window.event.returnValue="提示：\“退出系统\”请点系统的\“安全退出\”!";
          }
   }

//window.open('http://www.hao123.com','mywindow','toolbar=0;width=800;height=600,resizable=1,scrollbars=1');
//window.focus();
</script>