function fuc_browserDetermind() {
	var userAgent = navigator.userAgent.toLowerCase();
	
	if ((userAgent.indexOf("msie") != -1) && (userAgent.indexOf("opera") == -1) && (userAgent.indexOf("webtv") == -1)) {
		var version = parseInt(navigator.appVersion);
		if (version >= 4) {
			version = parseInt(userAgent.substring(userAgent.indexOf("msie ") + 5));
		}
		this.isIE = 1;
		this.lteIE5 = (version <= 5);
		this.lteIE6 = (version <= 6);
		this.gteIE7 = (version >= 7);
	} else {
		this.isSafari = (userAgent.indexOf("safari") != -1);
		this.isFirefox = (userAgent.indexOf("firefox") != -1);
		this.isOpera = (userAgent.indexOf("opera") != -1);
	}
}

var browser = new fuc_browserDetermind();