Function extend

src/prototype/dom/dom.js:3252–3266

* Element.extend(element) -> Element * * Extends the given element instance with all of the Prototype goodness and * syntactic sugar, as well as any extensions added via [[Element.addMethods]]. * (If the element instance was already extended, this is a no-op.) * * You only nee

(element)

   *  will also be extended with the methods from `Form.Methods`.
  **/
  function extend(element) {
    if (!element || elementIsExtended(element)) return element;
    if (element.nodeType !== Node.ELEMENT_NODE || element == window)
      return element;

    var methods = Object.clone(Methods),
     tagName = element.tagName.toUpperCase();

    // Add methods for specific tags.
    if (ByTag[tagName]) Object.extend(methods, ByTag[tagName]);

    extendElementWith(element, methods);
    EXTENDED[getUniqueElementID(element)] = true;
    return element;
  }

  // Because of the deficiency mentioned above, IE8 needs a very thin version
  // of Element.extend that acts like Prototype.K _except_ when the element