下面以最简单的asp来说明一下

1.代码加在一个全站都有调用的网页文件内

2.判断当前域名是否是www的二级域名或者一级域名

3.Request.ServerVariables("SERVER_NAME")意思的读取这个网页连接的域名部分

4.request.servervariables("http_url")意思是读取整个网页链接除了域名后的参数

<% if Request.ServerVariables("SERVER_NAME")="www.wangjunjiang.com"  or Request.ServerVariables("SERVER_NAME")="wangjunjiang.com" then %>

<!---识别手机或电脑的js开始--->
<script language="javascript"> 
(function(){
var res = GetRequest();
var par = res['index'];
if(par!='gfan'){
var ua=navigator.userAgent.toLowerCase();
var contains=function (a, b){
if(a.indexOf(b)!=-1){return true;}
};
//将下面的http://m.google.com改成你的wap手机版地址 如我的 http://m.yijile.com
var toMobileVertion = function(){
window.location.href = 'http://m.wangjunjiang.com/<%=request.servervariables("http_url")%>'
}
 
if(contains(ua,"ipad")||(contains(ua,"rv:1.2.3.4"))||(contains(ua,"0.0.0.0"))||(contains(ua,"8.0.552.237"))){return false}
if((contains(ua,"android") && contains(ua,"mobile"))||(contains(ua,"android") && contains(ua,"mozilla")) ||(contains(ua,"android") && contains(ua,"opera"))
||contains(ua,"ucweb7")||contains(ua,"iphone")){toMobileVertion();}
}
})();
function GetRequest() {
  var url = location.search; //获取url中"?"符后的字串
  var theRequest = new Object();
  if (url.indexOf("?") != -1) {
     var str = url.substr(1);
     strs = str.split("&");
     for(var i = 0; i < strs.length; i ++) {
        theRequest[strs[i].split("=")[0]]=unescape(strs[i].split("=")[1]);
     }
  }
  return theRequest;
}
</script>
<!---识别手机或电脑的js结束--->

<% end if %>