//判断是否微信登陆
function isWeiXin() {
var ua = window.navigator.userAgent.toLowerCase();
console.log(ua);//mozilla/5.0 (iphone; cpu iphone os 9_1 like mac os x) applewebkit/601.1.46 (khtml, like gecko)version/9.0 mobile/13b143 safari/601.1
if (ua.match(/MicroMessenger/i) == 'micromessenger') {
return true;
} else {
return false;
}
}
if(isWeiXin()){
console.log(" 是来自微信内置浏览器")
}else{
console.log("不是来自微信内置浏览器")
}

Mozilla/5.0 (iPhone; CPU iPhone OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Mobile/9B176 MicroMessenger/4.3.2

Mozilla/5.0 (Linux; U; Android 2.3.6; zh-cn; GT-S5660 Build/GINGERBREAD) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1 MicroMessenger/4.5.255

function is_weixn(){ 
var ua = navigator.userAgent.toLowerCase(); 
if(ua.match(/MicroMessenger/i)=="micromessenger") { 
return true; 
} else { 
return false; 
} 
} 

function is_weixin(){ 
if ( strpos($_SERVER['HTTP_USER_AGENT'], 'MicroMessenger') !== false ) { 
return true; 
} 
return false; 
}