/** version 1.1
 * getElementsByClassName has been added to the document-scope
 */

function addClass(element, className) {
    if (!hasClass(element, className)) {
        if (element.className) element.className += " " + className;
        else element.className = className;
    }
};

function removeClass(element, className) {
    var regexp = new RegExp("(^|\\s)" + className + "(\\s|$)");
    element.className = element.className.replace(regexp, "$2");
};

function hasClass(element, className) {
    var regexp = new RegExp("(^|\\s)" + className + "(\\s|$)");
    return regexp.test(element.className);
};

getElementsByClassName = function(className, tagName, fromElement) {
  var startNode = fromElement || document;
  var tagFilter = tagName || "*";
  var children = startNode.getElementsByTagName(tagFilter);
  var elements = new Array();
  
  for (var i = 0; i < children.length; i++) {
    var child = children[i];
    var classNames = child.className.split(' ');
    for (var j = 0; j < classNames.length; j++) {
      if (classNames[j] == className) {
        elements.push(child);
        break;
      }
    }
  }
  return elements;
}

document.getElementsByClassName = getElementsByClassName;
$C = getElementsByClassName;