js 判断设备的来源

   function deviceType(){
        var ua = navigator.userAgent;
        var agent = ["Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod"];
        for(var i=0; i<len,len = agent.length; i++){
            if(ua.indexOf(agent[i])>0){
                break;
            }
        }
    }
    deviceType();
    window.addEventListener('resize', function(){
        deviceType();
    })

    微信的 有些不太一样
    function isWeixin(){
        var ua = navigator.userAgent.toLowerCase();
        if(ua.match(/MicroMessenger/i)=='micromessenger'){
            return true;
        }else{
            return false;
        }
    }