/* add an event */
function addEvent(target, eventType, functionRef, capture) {
  if (typeof target.addEventListener != "undefined") {
    target.addEventListener(eventType, functionRef, capture);
  } else if (typeof target.attachEvent != "undefined") {
    target.attachEvent("on" + eventType, functionRef);
  } else {
    eventType = "on" + eventType;
    if (typeof target[eventType] == "function") {
      var oldListener = target[eventType];
      target[eventType] = function() {
        oldListener();
        return functionRef();
      }
    } else {
      target[eventType] = functionRef;
    }
  }
  return true;
}

function detachEventListener(target, eventType, functionRef, capture) {
  if (typeof target.removeEventListener != "undefined") {
    target.removeEventListener(eventType, functionRef, capture)
  } else if (typeof target.detachEvent != "undefined") {
    target.detachEvent("on" + eventType, functionRef);
  } else {
    target["on" + eventType] = null;
  }
  return true;
}

/* stack load functions */
function addLoadListener(fn) {
  if (typeof window.addEventListener != 'undefined') {
    window.addEventListener('load', fn, false);
  } else if (typeof document.addEventListener != 'undefined') {
    document.addEventListener('load', fn, false);
  } else if (typeof window.attachEvent != 'undefined'){
    window.attachEvent('onload', fn);
  } else {
    var oldfn = window.onload;
    if (typeof window.onload != 'function') {
      window.onload = fn;
    } else {
      window.onload = function() {
        oldfn();
        fn();
      };
    }
  }
}

/* get the target of an event */
function getEventTarget(event) {
  var targetElement = null;
  if (typeof event.target != "undefined") {
    targetElement = event.target;
  } else {
    targetElement = event.srcElement;
  } while (targetElement.nodeType == 3 && targetElement.parentNode != null) {
    targetElement = targetElement.parentNode;
  }
  return targetElement;
}

/* stop an event's default action */
function stopDefaultAction(event) {
  event.returnValue = false;
  if (typeof event.preventDefault != "undefined") {
    event.preventDefault();
  }
  return true;
}

/* get an array of all the elements that have an attribute with a specific value */
function getElementsByAttribute(attribute, attributeValue) {
  var elementArray = new Array();
  var matchedArray = new Array();

  if (document.all) {
    elementArray = document.all;
  } else { 
    elementArray = document.getElementsByTagName("*");
  }
  for (var i = 0; i < elementArray.length; i++) {
    if (attribute == "class") {
      var pattern = new RegExp("(^| )" + attributeValue + "( |$)");
      if (elementArray[i].className.match(pattern)) {
        matchedArray[matchedArray.length] = elementArray[i];
      }
    } else if (attribute == "for") {
      if (elementArray[i].getAttribute("htmlFor") || elementArray[i].getAttribute("for")) {
        if (elementArray[i].htmlFor == attributeValue) {
          matchedArray[matchedArray.length] = elementArray[i];
        }
      }
    } else if (elementArray[i].getAttribute(attribute) == attributeValue) {
      matchedArray[matchedArray.length] = elementArray[i];
    }
  }
  return matchedArray;
}