function Is ()	{   // convert all characters to lowercase to simplify testing
	    var agt=navigator.userAgent.toLowerCase();
	    // *** BROWSER VERSION ***
	    // Note: On IE5, these return 4, so use is.ie5up to detect IE5.
	    this.major = parseInt(navigator.appVersion);
	    this.minor = parseFloat(navigator.appVersion);
	
	    this.nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
	                && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
	                && (agt.indexOf('webtv')==-1));
	    this.nav4 = (this.nav && (this.major == 4));
	    this.navonly  = (this.nav && ((agt.indexOf(";nav") != -1) ||
	                     (agt.indexOf("; nav") != -1)) );
	    this.nav5 = (this.nav && (this.major == 5));
	    this.nav5up = (this.nav && (this.major >= 5));
	
	    this.ie   = (agt.indexOf("msie") != -1);
	    this.ie3  = (this.ie && (this.major < 4));
	    this.ie4  = (this.ie && (this.major == 4) && (agt.indexOf("msie 5.0")==-1) );
	    this.ie4up  = (this.ie  && (this.major >= 4));
	    this.ie5  = (this.ie && (this.major == 4) && (agt.indexOf("msie 5.0")!=-1) );
	    this.ie5up  = (this.ie  && !this.ie3 && !this.ie4);
	}
		
	var is;
	var isIE3Mac = false;
	
	if ((navigator.appVersion.indexOf("Mac")!=-1) && (navigator.userAgent.indexOf("MSIE")!=-1) && 
	(parseInt(navigator.appVersion)==3))
	       isIE3Mac = true;
	else   is = new Is();
	
	
	function rollOn(imgSrc1,layerIDa) {
		if	(is.ie4up||is.nav5up)	{document.images[imgSrc1].src = "/images/medialookup/ctf/rm/channel/" + imgSrc1 + "_h.gif";}
		else if	(is.nav4)	{document.layers[layerIDa].document.images[imgSrc1].src = "/images/medialookup/ctf/rm/channel/" + imgSrc1 + "_h.gif";}
	}
	function rollOff(imgSrc1,layerIDa) {
		if	(is.ie4up||is.nav5up)	{document.images[imgSrc1].src = "/images/medialookup/ctf/rm/channel/" + imgSrc1 + ".gif";}
		else if	(is.nav4)	{document.layers[layerIDa].document.images[imgSrc1].src = "/images/medialookup/ctf/rm/channel/" + imgSrc1 + ".gif";}
	}