// Define images
logo_off = new Image;
logo_on = new Image;
logomain_off = new Image;
logomain_on = new Image;

function load_images() {
  // Off images
  logo_off.src = "/bells/images/logoblue.gif";
  logomain_off.src = "/bells/images/logoblue.gif";

  // On images
  logo_on.src = "/bells/images/logoblueneg.gif";
  logomain_on.src = "/bells/images/logoblueneg.gif";
}

function button_on(imgname) {
  if(document.images) {
    document.images[imgname].src = eval(imgname + "_on.src");
  }
}

function button_off(imgname) {
  if(document.images) {
    document.images[imgname].src = eval(imgname + "_off.src");
  }
}