var norm = new Array();
var imgArray = new Array('curr');
imgArray[0] = "curr";

// Preload
if (document.images) {
  var over = new Array();
  var press = new Array();
  for(i=0; i< imgArray.length; i++) {
    over[i] = new Image();
    over[i].src = "img/ttmonialsNav_"+imgArray[i]+"_a.gif";
  }
}

function on(num) {
  if(document.images) {
    norm[num] = document.images[imgArray[num]].src;
    document.images[imgArray[num]].src = over[num].src;
  }
}

function off(num) {
  if(document.images) document.images[imgArray[num]].src = norm[num];
}