用js实现判断当前网址的来路如果不是指定的来路就跳转到指定页面

<script type="text/javascript">
if(self!=top){top.location=self.location;}
var ref=document.referrer;
var domains=new Array("jb51.net/","jb51.cn/","jb51.com.cn/");
var refpass=false;
for(i=0;i<=domains.length;i++){if(ref.indexOf(domains[i])>0){refpass=true;break;}}
if(ref==""){refpass=true}
if(!refpass){window.location.href='https://www.jb51.net';}
</script>

<script>
function isMatch(str1,str2)
{ 
var index = str1.indexOf(str2);
if(index==-1) return false;
return true;
}
alert(window.location.hostname);
if (isMatch(window.location.hostname,'www.jb51.net') == false){window.location.href="https://www.jb51.net";}
</script>

function gotourl()
{
 var url = "https://www.jb51.net";
 var localurl = document.url;
 if( localurl.substring(0,url.length) != url )
 {
  location.href=url;
 }
}
gotourl();