判斷用戶是否安裝微信APP（URL_scheme 協議判斷）

核心函數：
//打開（下載）App
function openApp(){
    var ua = window.navigator.userAgent.toLowerCase();
    //微信
    if(ua.match(/MicroMessenger/i) === 'micromessenger'){
        window.location.href='downLoadForPhone';
    }else{//非微信瀏覽器
        if (navigator.userAgent.match(/(iPhone|iPod|iPad);?/i)) {

            var loadDateTime = new Date();
            window.setTimeout(function() {
                var timeOutDateTime = new Date();
                if (timeOutDateTime - loadDateTime < 5000) {
                    window.location = "itms-apps://";//ios下載地址
                } else {
                    window.close();
                }
            },2000);
            window.location = "weixin://";
        }else if (navigator.userAgent.match(/android/i)) {
            var state = null;
            try {
                // window.location = 'schema://';
                setTimeout(function(){
                    window.location= "weixin://"; //android下載地址
                },2000);
            } catch(e) {}
        }
    }
}

可能出現的問題：

使用 URL_scheme 協議無法打開 App Store 下載頁 "itms-apps://" 只能打開空白頁

解決方法：進入 https://itunes.apple.com/cn 頁面搜索需要的 app 使用該下載頁鏈接

應用寶判斷需接入騰訊服務“微下載”，企業賬號，個人測試賬號注冊需手持身份證照

Test 例子：

//打開（下載）App
function openApp(){
    var ua = window.navigator.userAgent.toLowerCase();
    //微信
    if(ua.match(/MicroMessenger/i) == 'micromessenger'){
        alert('已打開微信，請關注【小五服裝店】微信公眾號或者在微信搜索【小五服裝店】小程序領取哦~');
    }else{//非微信瀏覽器
        if (navigator.userAgent.match(/(iPhone|iPod|iPad);?/i)) {
            window.location = "weixin://";
            var loadDateTime = new Date();
            window.setTimeout(function() {
                var timeOutDateTime = new Date();
                if (timeOutDateTime - loadDateTime < 5000) {
                    // window.location = "itms-apps://";//ios下載地址
                    // window.location = "https://itunes.apple.com/cn/app/wei-xin/id414478124?mt=8";//ios微信web下載地址
                    window.location = "https://itunes.apple.com/cn/app/%E5%BE%AE%E4%BF%A1/id414478124?mt=8&v0=WWW-GCCN-ITSTOP100-FREEAPPS&l=&ign-mpt=uo%3D4";//ios微信web下載地址
                } else {
                    window.close();
                }
            },3000);
            // window.location = "weixin://";
        }else if (navigator.userAgent.match(/android/i)) {
            try {
                window.location = "weixin://";
                setTimeout(function(){
                    window.location = "http://a.app.qq.com/o/simple.jsp?pkgname=com.tencent.mm#opened"; //android下載地址
                    // window.location= "http://weixin.qq.com/"; //android微信web下載地址
                },3000);
            } catch(e) {}
        }
    }
}