$(function(){  
        var u = navigator.userAgent;  
        var isAndroid = u.indexOf(‘Android‘) > -1 || u.indexOf(‘Adr‘) > -1; //android终端  
        var isiOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端  
        if(isAndroid){  
            alert("android");  
        }else if(isiOS){  
            alert("ios");  
        }else{  
        }  
        var ua = window.navigator.userAgent.toLowerCase();  
        if (ua.match(/MicroMessenger/i) == ‘micromessenger‘) {  
            alert("微信");  
        } else {  
            alert("非微信");  
        }  
});