判断ie8以下 或者ie9以下

1、各种浏览器下载

http://browsehappy.osfipin.com/

2、ie8浏览器以下

if(![].map) {
        // IE8浏览器
        alert('ie8浏览器')
    }

3、ie9浏览器以下

(function(w) {
		if(!("WebSocket" in w && 2 === w.WebSocket.CLOSING)) {
			var d = document.createElement("div");
			d.className = "browsehappy";
			d.innerHTML = '<div style="width:100%;height:100px;font-size:20px;line-height:100px;text-align:center;background-color:#E90D24;color:#fff;margin-bottom:40px;">\u4f60\u7684\u6d4f\u89c8\u5668\u5b9e\u5728<strong>\u592a\u592a\u65e7\u4e86</strong>\uff0c\u592a\u592a\u65e7\u4e86 <a target="_blank" href="http://browsehappy.osfipin.com/" style="background-color:#31b0d5;border-color: #269abc;text-decoration: none;padding: 6px 12px;background-image: none;border: 1px solid transparent;border-radius: 4px;color:#FFEB3B;">\u7acb\u5373\u5347\u7ea7</a></div>';
			var f = function() {
				var s = document.getElementsByTagName("body")[0];
				if("undefined" == typeof(s)) {
					setTimeout(f, 10)
				} else {
					s.insertBefore(d, s.firstChild)
				}
			};
			f()
		}
	}(window));