if (document.images) {
  pic1on= new Image();
  upcomingHighlight.src="./images/upcomingHighlight.gif";
}

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

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

function clickdown(imgName) {
  if (document.images) {
    imgDown=eval(imgName + "down.src");
    document[imgName].src=imgDown;
  }
}