单击浏览器右上角的X弹出提示窗口

单击浏览器右上角的X弹出提示窗口，简单实现。

<script language="javascript">
   window.onunload   =   function   () 
  { 
     if   (event.clientY   <   0   &&   event.clientX> document.body.scrollWidth)   { 
      //event.returnValue   =   'Are   you   sure   you   want   to   leave   the   page? '; 
      window.alert('欢迎光临爱智旮旯的博客！')
    } 
  } 
  </script>