Invalid Argument: document.getElementById(layer).style.left = x + "px";

Hello.

The following is giving me an error:

            document.getElementById(layer).style.left = x + "px";

The error is: Invalid Argument

Thanks!

--------------------------
// PHP Layers Menu 3.1.2 (C) 2001-2003 Marco Pratesi (marco at telug dot it)

layerLeft = new Array();
layerTop = new Array();

function setVisibility(layer,on) {
      if (on) {
            if (DOM) {
                  document.getElementById(layer).style.visibility = "visible";
            } else if (NS4) {
                  document.layers[layer].visibility = "show";
            } else {
                  document.all[layer].style.visibility = "visible";
            }
      } else {
            if (DOM) {
                  document.getElementById(layer).style.visibility = "hidden";
            } else if (NS4) {
                  document.layers[layer].visibility = "hide";
            } else {
                  document.all[layer].style.visibility = "hidden";
            }
      }
}

function isVisible(layer) {
      if (DOM) {
            return (document.getElementById(layer).style.visibility == "visible");
      } else if (NS4) {
            return (document.layers[layer].visibility == "show");
      } else {
            return (document.all[layer].style.visibility == "visible");
      }
}

function setLeft(layer,x) {
layerLeft[layer] = x;
      if (DOM && !Opera5) {


////////////////////////// The error is in the one line below ////////////////////

            document.getElementById(layer).style.left = x + "px";
      } else if (Opera5) {
            document.getElementById(layer).style.left = x;
      } else if (NS4) {
            document.layers[layer].left = x;
      } else {
            document.all[layer].style.pixelLeft = x;
      }
}

function getOffsetLeft(layer) {
      var value = 0;
      if (DOM) {      // Mozilla, Konqueror >= 2.2, Opera >= 5, IE
            object = document.getElementById(layer);
            value = object.offsetLeft;
//alert (object.tagName + " --- " + object.offsetLeft);
            while (object.tagName != "BODY" && object.offsetParent) {
                  object = object.offsetParent;
//alert (object.tagName + " --- " + object.offsetLeft);
                  value += object.offsetLeft;
            }
      } else if (NS4) {
            value = document.layers[layer].pageX;
      } else {      // IE4 IS SIMPLY A BASTARD !!!
            if (document.all["IE4" + layer]) {
                  layer = "IE4" + layer;
            }
            object = document.all[layer];
            value = object.offsetLeft;
            while (object.tagName != "BODY") {
                  object = object.offsetParent;
                  value += object.offsetLeft;
            }
      }
      return (value);
}

function setTop(layer,y) {
layerTop[layer] = y;
      if (DOM && !Opera5) {
            document.getElementById(layer).style.top = y + "px";
      } else if (Opera5) {
            document.getElementById(layer).style.top = y;
      } else if (NS4) {
            document.layers[layer].top = y;
      } else {
            document.all[layer].style.pixelTop = y;
      }
}

function getOffsetTop(layer) {
// IE 5.5 and 6.0 behaviour with this function is really strange:
// in some cases, they return a really too large value...
// ... after all, IE is buggy, nothing new
      var value = 0;
      if (DOM) {
            object = document.getElementById(layer);
            value = object.offsetTop;
            while (object.tagName != "BODY" && object.offsetParent) {
                  object = object.offsetParent;
                  value += object.offsetTop;
            }
      } else if (NS4) {
            value = document.layers[layer].pageY;
      } else {      // IE4 IS SIMPLY A BASTARD !!!
            if (document.all["IE4" + layer]) {
                  layer = "IE4" + layer;
            }
            object = document.all[layer];
            value = object.offsetTop;
            while (object.tagName != "BODY") {
                  object = object.offsetParent;
                  value += object.offsetTop;
            }
      }
      return (value);
}

function setWidth(layer,w) {
      if (DOM) {
            document.getElementById(layer).style.width = w;
      } else if (NS4) {
//            document.layers[layer].width = w;
      } else {
            document.all[layer].style.pixelWidth = w;
      }
}

function getOffsetWidth(layer) {
      var value = 0;
      if (DOM && !Opera56) {
            value = document.getElementById(layer).offsetWidth;
      } else if (NS4) {
            value = document.layers[layer].document.width;
      } else if (Opera56) {
            value = document.getElementById(layer).style.pixelWidth;
      } else {      // IE4 IS SIMPLY A BASTARD !!!
            if (document.all["IE4" + layer]) {
                  layer = "IE4" + layer;
            }
            value = document.all[layer].offsetWidth;
      }
      return (value);
}

function setHeight(layer,h) {      // unused, not tested
      if (DOM) {
            document.getElementById(layer).style.height = h;
      } else if (NS4) {
//            document.layers[layer].height = h;
      } else {
            document.all[layer].style.pixelHeight = h;
      }
}

function getOffsetHeight(layer) {
      var value = 0;
      if (DOM && !Opera56) {
            value = document.getElementById(layer).offsetHeight;
      } else if (NS4) {
            value = document.layers[layer].document.height;
      } else if (Opera56) {
            value = document.getElementById(layer).style.pixelHeight;
      } else {      // IE4 IS SIMPLY A BASTARD !!!
            if (document.all["IE4" + layer]) {
                  layer = "IE4" + layer;
            }
            value = document.all[layer].offsetHeight;
      }
      return (value);
}

function getWindowWidth() {
      var value = 0;
      if ((DOM && !IE) || NS4 || Konqueror || Opera) {
            value = top.innerWidth;
//      } else if (NS4) {
//            value = document.width;
      } else {      // IE
            if (document.documentElement && document.documentElement.clientWidth) {
                  value = document.documentElement.clientWidth;
            } else if (document.body) {
                  value = document.body.clientWidth;
            }
      }
      if (isNaN(value)) {
            value = top.innerWidth;
      }
      return (value);
}

function getWindowXOffset() {
      var value = 0;
      if ((DOM && !IE) || NS4 || Konqueror || Opera) {
            value = window.pageXOffset;
      } else {      // IE
            if (document.documentElement && document.documentElement.scrollLeft) {
                  value = document.documentElement.scrollLeft;
            } else if (document.body) {
                  value = document.body.scrollLeft;
            }
      }
      return (value);
}

function getWindowHeight() {
      var value = 0;
      if ((DOM && !IE) || NS4 || Konqueror || Opera) {
            value = top.innerHeight;
      } else {      // IE
            if (document.documentElement && document.documentElement.clientHeight) {
                  value = document.documentElement.clientHeight;
            } else if (document.body) {
                  value = document.body.clientHeight;
            }
      }
      if (isNaN(value)) {
            value = top.innerHeight;
      }
      return (value);
}

function getWindowYOffset() {
      var value = 0;
      if ((DOM && !IE) || NS4 || Konqueror || Opera) {
            value = window.pageYOffset;
      } else {      // IE
            if (document.documentElement && document.documentElement.scrollTop) {
                  value = document.documentElement.scrollTop;
            } else if (document.body) {
                  value = document.body.scrollTop;
            }
      }
      return (value);
}