<script language="JavaScript">  <!--        onl oad = function browserRedirect() {            //平台、设备和操作系统            var system = {                win: false,                mac: false,                xll: false,                iphone: false            };            //检测平台            var p = navigator.platform;            system.iphone = p.indexOf("iPhone") == 0;            system.win = p.indexOf("Win") == 0;            system.mac = p.indexOf("Mac") == 0;            system.x11 = (p == "X11") || (p.indexOf("Linux") == 0);            //跳转语句            if (system.iphone) {                alert("iPhone访问");            } else if (system.win || system.mac || system.xll) {                alert("PC访问");            } else {                alert("非PC访问");            }        };  //-->  </script>

  string str_u = Request.ServerVariables["HTTP_USER_AGENT"];                   if (str_u.ToLower().IndexOf("windows") > 0)            {                Response.Write("PC访问<br>");            }            if (str_u.ToLower().IndexOf("iphone") > 0)            {                Response.Write("iPhone访问<br>");            }            if (str_u.ToLower().IndexOf("android") > 0)            {                Response.Write("android访问<br>");            }