var NS4DOM = document.layers ? true:false;
var IEDOM = document.all ? true:false;
var W3CDOM = document.getElementById ? true: false;

function ChooseCategory(div, img, pth) {
  var divobj = getObject(div);
  var imgobj = getObject(img);
  
  if (divobj.style.display == 'none') {
    divobj.style.display = 'block';
    imgobj.src           = pth + 'images/collapse.jpg';
  } else {
    divobj.style.display = 'none';
    imgobj.src           = pth + 'images/expand.jpg';
  }
}

function getObject(id) {
    var ref;
    
    if (NS4DOM)
      ref = "document." + id;
    else if (IEDOM)
      ref = id;
    else
      ref = "document.getElementById('" + id + "')";
    
    var object = eval(ref);
    return object;
}