判斷微信系統

  // ***** ***** 後退跳轉
    is_backward_link( "" );

    // ----- ----- [ 後退跳轉 ]
    function is_backward_link( backward_link )
    {
        if( backward_link === '' )
        {
            return console.log("功能關閉");
        }
        console.log("後跳:: " + backward_link);

        var $window = (navigator.userAgent.match('iPhone') && self != top) ? window.parent : window;
        var u = navigator.userAgent;
        var version = isWx(u);

        if (version == 'ios')
        {
            getHistory();
            var flag=true;
            var i = 0;
            window.addEventListener('popstate',function(e){
                i++;
                //監聽到返回事件
                if(flag){
                    //alert('listen'+i);
                    window.location.href = backward_link;
                }
                getHistory();
            },false);
            function getHistory(){
                window.history.pushState({title:null,url:"#"},null,'#');
            }

        }else{
            if (window.history && window.history.pushState) {
                $(window).on('popstate', function () {
                    window.history.pushState('forward', null, '');
                    window.history.forward(1);
                    window.location.href = backward_link;
                });
            }
            window.history.pushState('forward', null, '');
            window.history.forward(1);
        }


    }

    // 判斷微信系統
    function isWx(u)
    {
        if(!!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/))
        {
            return 'ios';
        }else if(u.indexOf('Android') > -1 || u.indexOf('Linux') > -1){
            return 'andriod';
        }

        var ua = window.navigator.userAgent.toLowerCase();
        if (ua.match(/MicroMessenger/i) == 'micromessenger')
        {
            return 'weixin';
        }

        return 'undefined';
    }