document.getElementBy("id")与$("#id")有什么区别

document.getElementBy("id")

function $()
{
  var elements = new Array();
  for (var i = 0; i < arguments.length; i++)
  {
    var element = arguments[i];
    if (typeof element == 'string')
      element = document.getElementById(element);
    if (arguments.length == 1)
      return element;
    elements.push(element);
  }
  return elements;
}

function $(objectId) {
if(document.getElementById && document.getElementById(objectId)) {
 return document.getElementById(objectId);// W3C DOM
 } else if (document.all && document.all(objectId)) {
  return document.all(objectId);// MSIE 4 DOM
 } else if (document.layers && document.layers[objectId]) {
  return document.layers[objectId];// NN 4 DOM.. note: this won't find nested layers
 } else {
  return false;
 }
}