js判断手机是否安装了某个APP,如果安装了就打开，没安装就下载

//打开（下载）App
function openApp(){
var ua = window.navigator.userAgent.toLowerCase();
//微信
if(ua.match(/MicroMessenger/i) == 'micromessenger'){
window.location.href='downLoadForPhone';
}else{//非微信浏览器
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 = "";//ios下载地址
} else {
window.close();
}
},2000);
window.location = "schema://";
}else if (navigator.userAgent.match(/android/i)) {
var state = null;
try {
window.location = 'schema://';
setTimeout(function(){
window.location= ""; //android下载地址

},500);
} catch(e) {}
}
}
}

window.location.href = 'weibo://';
window.location.href = 'weixin://';