function bwcheck(){
	this.ver=navigator.appVersion;
	this.agent=navigator.userAgent;

	this.dom=document.getElementById?1:0;

	this.ie5=(this.ver.toLowerCase().indexOf("msie 5.0")>-1 && this.dom)?1:0;
	this.ie55=(this.ver.toLowerCase().indexOf("msie 5.5")>-1 && this.dom)?1:0;
	this.ie6=(this.ver.toLowerCase().indexOf("msie 6")>-1 && this.dom)?1:0;
	this.ie4=(document.all && !this.dom)?1:0;
	this.ie=this.ie4||this.ie5||this.ie6;

	this.ns6=(this.dom && parseInt(this.ver) >= 5) ?1:0;
	this.ns4=(document.layers && !this.dom)?1:0;

	this.opera5=this.agent.toLowerCase().indexOf("opera 5")>-1;

	this.mac=this.agent.toLowerCase().indexOf("mac")>-1;
	this.win=this.agent.toLowerCase().indexOf("win")!=-1;
	this.xp=this.agent.toLowerCase().indexOf("windows nt 5.1")!=-1;

	this.bw=(this.ie6 || this.ie55 || this.ie5 || this.ie4 || this.ns4 || this.ns6 || this.opera5 || this.dom);
	return this;
}

var bw=new bwcheck();