function isInstalled(){
        var urlFrag = ‘somepars‘;
        var the_href = ‘market://****‘;//获得下载链接
        window.location.href = "appname://start" + urlFrag;//打开某手机上的某个app应用
        setTimeout(function(){
            window.location.href = the_href;//如果超时就跳转到app下载页
        },800);
    }

function isInstalled() {
        var timeout, t = 1000,
             hasApp = true,
             urlFrag = ‘somepars‘;
        url = "appname://start" + urlFrag ;
         var openScript = setTimeout(function() {
             if (!hasApp) {
                 var durl = ‘market://******‘;
                 window.location.href = durl;
             }
             document.body.removeChild(ifr);
         }, 2000)

         var t1 = Date.now();
         var ifr = document.createElement("iframe");
         ifr.setAttribute(‘src‘, url);
         ifr.setAttribute(‘style‘, ‘display:none‘);
         document.body.appendChild(ifr);
         timeout = setTimeout(function() {
             var t2 = Date.now();
             if (!t1 || t2 - t1 < t + 100) {
                 hasApp = false;
             }
        }, t);
    }