判断浏览器是不是微信

   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;
    }
}
// 使用方法
    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")
    }