function Check() {
	 var tip = navigator.appName;
	 var ver = parseInt(navigator.appVersion);
	if (tip=="Netscape"){
		if(ver>=4 && ver<5)
			tip = "ns";
		if(ver>=5)
			tip = "ns6";
	}
	else if (tip=="Microsoft Internet Explorer") 
		tip = "ie";

	 this.ns = (tip=="ns")
	 this.ie = (tip=="ie" && ver>=4)
	 this.ns6 = (tip=="ns6")
}
is = new Check();