浏览器判断

//低版本浏览器提示
	function myBrowser() {
		var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串
		var isOpera = userAgent.indexOf("Opera") > -1; //判断是否Opera浏览器
		var isIE = userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera; //判断是否IE浏览器
		var isFF = userAgent.indexOf("Firefox") > -1; //判断是否Firefox浏览器
		var isSafari = userAgent.indexOf("Safari") > -1; //判断是否Safari浏览器
		if(isIE) {
			var IE5 = IE55 = IE6 = IE7 = IE8 = false;
			var reIE = new RegExp("MSIE (\\d+\\.\\d+);");
			reIE.test(userAgent);
			var fIEVersion = parseFloat(RegExp["$1"]);
			IE55 = fIEVersion == 5.5;
			IE6 = fIEVersion == 6.0;
			IE7 = fIEVersion == 7.0;
			IE8 = fIEVersion == 8.0;
			if(IE55) {
				return "IE55";
			}
			if(IE6) {
				return "IE6";
			}
			if(IE7) {
				return "IE7";
			}
			if(IE8) {
				return "IE8";
			}
		} //isIE end
		if(isFF) {
			return "FF";
		}
		if(isOpera) {
			return "Opera";
		}
	} //myBrowser() end
	//以下是调用上面的函数
//	if(myBrowser() == 'IE55' || 'IE6' || 'IE7' || 'IE8') {
//		$('body').append(ieAlert_html);
//	};