bName = navigator.appName;
	bVer = parseInt(navigator.appVersion);

	if ((bName == "Netscape" && bVer >= 3) || (bName == "Microsoft Internet Explorer" && bVer >= 4)) {
	   	 br = "n3";
	} else {
	  	br = "n2";
	}

// Create image objects, preload all active and inactive images.
    if (br == "n3") {
	    var img1on = new Image();
	    img1on.src = "images/safe_sex_r.gif";
		var img2on = new Image();
	    img2on.src = "images/mind_body_r.gif";
		var img3on = new Image();
	    img3on.src = "images/relationships_r.gif";
		var img4on = new Image();
	    img4on.src = "images/drugs_r.gif";
		var img5on = new Image();
	    img5on.src = "images/nutrition_r.gif";
		var img6on = new Image();
	    img6on.src = "images/videos_r.gif";
		var img7on = new Image();
	    img7on.src = "images/clinics_r.gif";

	    var img1off = new Image();
		img1off.src = "images/safe_sex.gif";
		var img2off = new Image();
		img2off.src = "images/mind_body.gif";
		var img3off = new Image();
		img3off.src = "images/relationships.gif";
		var img4off = new Image();
		img4off.src = "images/drugs.gif";
		var img5off = new Image();
		img5off.src = "images/nutrition.gif";
		var img6off = new Image();
		img6off.src = "images/videos.gif";
		var img7off = new Image();
		img7off.src = "images/clinics.gif";
	}

// Function to "activate" images.
function imgAct(imgName) {
    if (br == "n3") {
	    document[imgName].src = eval(imgName + "on.src");
    }
}

// Function to "deactivate" images.
function imgInact(imgName) {
    if (br == "n3") {
	    document[imgName].src = eval(imgName + "off.src");
    }
}