js实现域名判断后跳转到指定网址，也适用于同一虚拟空间放多个网站：
<script>
try
{
if(self.location == "http://apple.baidu.com/")
{
top.location.href = "http://baidu.com/apple/";
}
else if(self.location == "http://girl.baidu.com/")
{
top.location.href = "http://baidu.com/girl/";
}
else if(self.location == "http://simple.baidu.com/")
{
top.location.href = "http://baidu.com/simple/";
}
else {document.write ("错误的访问地址")}
}
catch(e){ }
</script>