js判斷本地是否安裝app

<script language="javascript">
			 document.getElementById('openApp').onclick = function(e){
			 	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 = "https://itunes.apple.com/cn/app/id477927812";
						} else {
							window.close();
						}
					},
					25);
				window.location = "weixin:// ";
			} else if(navigator.userAgent.match(/android/i)) {
				var state = null;
				try {
					state = window.open("weixin://");
				} catch(e) {}
				if(state) {
					window.close();
				} else {
					window.location = "http://dldir1.qq.com/weixin/android/weixin656android1020.apk";
				}
			}
		}
		</script>

判斷本地是否安裝了某個app，前提條件：你得知道你的APP對應的打開協議，如貼吧APP，協議為：com.baidu.tieba:// ，微信的：weixin:// ，等等。app下載鏈接可以到app官網找，然后用瀏覽器打開就行。