// the back to top animated when the cursor is over it.
backtop_on  = new Image();   
backtop_off = new Image();
backtop_on.src  = '../images/backtop-on.jpg';
backtop_off.src = '../images/backtop-off.jpg';
function activate(image) {
      imagesrc = eval(image + '_on.src');
      document[image].src = imagesrc;
}
function deactivate(image) {
      imagesrc = eval(image + "_off.src");
      document[image].src = imagesrc;
}