判断浏览器版本

<script language="javascript">
if(navigator.appName == "Microsoft Internet Explorer")
{
  if(navigator.appVersion.match(/6./i)=='6.')
  {
    window.open('ie6_page.htm','MSIE6');
  }else{
    window.open('ie_page.htm','MSIE');
  }
}

if(navigator.appName == "Netscape")
{
  if(navigator.appVersion.match(/4./i)=='4.')
  {
    window.open('ns4_page.htm','NS4');
  }else{
    window.open('ns_page.htm','NS');
  }
}

window.opener=null;
window.close();
</script>