/* 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;
}

/* use this to get a string of what browser the user has */
function identifyBrowser() {
  var agent = navigator.userAgent.toLowerCase();
  if (typeof navigator.vendor != "undefined" && navigator.vendor == "KDE" && typeof window.sidebar != "undefined") {
    return "kde";
  } else if (typeof window.opera != "undefined") {
    var version = parseFloat(agent.replace(/.*opera[\/ ]([^ $]+).*/, "$1"));
    if (version >= 7) {
      return "opera7";
    } else if (version >= 5) {
      return "opera5";
    }
    return false;
  }
  else if (typeof document.all != "undefined") {
    if (typeof document.getElementById != "undefined") {
      var browser = agent.replace(/.*ms(ie[\/ ][^ $]+).*/, "$1").replace(/ /, "");

      if (typeof document.uniqueID != "undefined") {
        if (browser.indexOf("5.5") != -1) {
          return browser.replace(/(.*5\.5).*/, "$1");
        } else {
          return browser.replace(/(.*)\..*/, "$1");
        }
      } else {
        return "ie5mac";
      }
    }
    return false;
  } else if (typeof document.getElementById != "undefined") {
    if (navigator.vendor.indexOf("Apple Computer, Inc.") != -1) {
      if (typeof window.XMLHttpRequest != "undefined") {
        return "safari1.2";
      }
      return "safari1";
    } else if (agent.indexOf("gecko") != -1) {
      return "mozilla";
    }
  }
  return false;
}

/* enter a cookie name to get its value */
function readCookie(name) {
    var cookieCrumbs = document.cookie.split(';');
    var nameToFind = name + '=';
    for (var i = 0; i < cookieCrumbs.length; i++) {
        var crumb = cookieCrumbs[i];
        while (crumb.charAt(0) == ' ') {
            crumb = crumb.substring(1, crumb.length); /* delete spaces */
        }
        if (crumb.indexOf(nameToFind) == 0) {
            return crumb.substring(nameToFind.length, crumb.length);
        }
    }
    return null;
}
function createCookie(name, value, days) {
    var expires = '';
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days*24*60*60*1000));
        var expires = '; expires=' + date.toGMTString();
    }
    document.cookie = name + '=' + value + expires + '; path=/';
}
function eraseCookie(name) {
    createCookie(name, '', -1);
}

function getViewportSize() {
  var size = [0,0];

  if (typeof window.innerWidth != 'undefined') {
    size = [
        window.innerWidth,
        window.innerHeight
    ];
  } else if (typeof document.documentElement != 'undefined'
      && typeof document.documentElement.clientWidth != 'undefined'
      && document.documentElement.clientWidth != 0) {
    size = [
        document.documentElement.clientWidth,
        document.documentElement.clientHeight
    ];
  } else {
    size = [
        document.getElementsByTagName('body')[0].clientWidth,
        document.getElementsByTagName('body')[0].clientHeight
    ];
  }
  return size;
}

function toggleSelects(vis) {
  if (typeof document.uniqueID != 'undefined'
      && typeof document.body.style.scrollbarTrackColor == 'undefined') {
    var selects = document.getElementsByTagName('select');
    for (var i = 0; i < selects.length; i++) {
      selects[i].style.visibility = vis;
    }
    return true;
  }
  return false;
}