if (document.images) {

			johnon = new Image();
            johnon.src = "/images/john_on.jpg";
			johnoff = new Image();
            johnoff.src = "/images/john.jpg";

			}

function img_act(imgName) {
	if (document.images){
    	imgOn = eval(imgName + "on.src");
        document [imgName].src = imgOn;
    }
}

function img_end(imgName) {
	if (document.images){
    	imgOff = eval(imgName + "off.src");
        document [imgName].src = imgOff;
    }
}