默认打开页面内框架名为main的框架，并加载intro.asp，若传入值，就打开url。
<script language="javascript">
function getPram(source, name)
{
var reg = new RegExp("(^|\\?|&)"+ name +"=([^&]*)(\\s|&|$)", "i");
if (reg.test(source)) return RegExp.$2; return "";
}
vu=location.href
url=getPram(vu,"url");
if(url==""){url="intro.asp";}
document.writeln(" <iframe src=\""+url+"\" name=\"main\" id=\"main\" width=\"750\" height=\"560\" scrolling=\"auto\" frameborder=\"0\" allowtransparency=\"true\" \/>");
document.writeln("<\/iframe>");
</script>