判断是否某App

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">
<title>判断手机是否安装微信</title>
</head>
<body>
<a href="javascript:testApp('weixin://')" class="dl-btn" id="download">打开微信</a>
<script>
function testApp(url) {
var timeout, t = 1000, hasApp = true;
setTimeout(function () {
if (!hasApp) {
//没有安装微信
var r=confirm("您没有安装微信,请先安装微信!");
if (r==true){
location.href="http://weixin.qq.com/"
}
}else{
//安装微信
}
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);
}
//判断访问终端
var browser={
versions:function(){
var u = navigator.userAgent, app = navigator.appVersion;
return {
trident: u.indexOf('Trident') > -1, //IE内核
presto: u.indexOf('Presto') > -1, //opera内核
webKit: u.indexOf('AppleWebKit') > -1, //苹果、谷歌内核
gecko: u.indexOf('Gecko') > -1 && u.indexOf('KHTML') == -1,//火狐内核
mobile: !!u.match(/AppleWebKit.*Mobile.*/), //是否为移动终端
ios: !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/), //ios终端
android: u.indexOf('Android') > -1 || u.indexOf('Linux') > -1, //android终端或者uc浏览器
iPhone: u.indexOf('iPhone') > -1 , //是否为iPhone或者QQHD浏览器
iPad: u.indexOf('iPad') > -1, //是否iPad
webApp: u.indexOf('Safari') == -1, //是否web应该程序,没有头部与底部
weixin: u.indexOf('MicroMessenger') > -1, //是否微信 (2015-01-22新增)
qq: u.match(/\sQQ/i) == " qq" //是否QQ
};
}(),
language:(navigator.browserLanguage || navigator.language).toLowerCase()
}
</script>
</body>
</html>javascript