// Rollover  v2.0.1

// documentation: http://www.dithered.com/javascript/rollover/index.html

// license: http://creativecommons.org/licenses/by/1.0/

// code by Chris Nott (chris[at]dithered[dot]com)
function isDefined(property) {

  return (typeof property != 'undefined');

}



var rolloverInitialized = false;

function rolloverInit() {

   if (!rolloverInitialized && isDefined(document.images)) {

      

      // get all images (including all <input type="image">s)

      // use getElementsByTagName() if supported

      var images = new Array();

      if (isDefined(document.getElementsByTagName)) {

         images = document.getElementsByTagName('img');

         var inputs = document.getElementsByTagName('input');

         for (var i = 0; i < inputs.length; i++) {

            if (inputs[i].type == 'image') {

               images[images.length] = inputs[i];

            }

         }

      }

      

      // otherwise, use document.images and document.forms collections

      // remove if not supporting IE4, Opera 4-5

      else {

         images = document.images;

         inputs = new Array();

         for (var formIndex = 0; formIndex < document.forms.length; formIndex++) {

            for (var elementIndex = 0; elementIndex < document.forms.elements.length; elementIndex++) {

               if (isDefined(document.forms.elements[i].src)) {

                  inputs[inputs.length] = document.forms.elements[i];

               }

            }

         }

      }

      

      // get all images with '_off.' in src value

      for (var i = 0; i < images.length; i++) {

         if (images[i].src.indexOf('_off.') != -1) {

            var image = images[i];

            

            // store the off state filename in a property of the image object

            image.offImage = new Image();

            image.offImage.src = image.src;

            

            // store the on state filename in a property of the image object

            // (also preloads the on state image)

            image.onImage = new Image();

            image.onImage.imageElement = image;

            

            // add onmouseover and onmouseout event handlers once the on state image has loaded

            // Safari's onload is screwed up for off-screen images; temporary fix

            if (navigator.userAgent.toLowerCase().indexOf('safari') != - 1) {

               image.onmouseover = function() {

                  this.src = this.onImage.src;

               };

               image.onmouseout = function() {

                  this.src = this.offImage.src;

               };

            }

            else {

               image.onImage.onload = function() {

                  this.imageElement.onmouseover = function() {

                     this.src = this.onImage.src;

                  };

                  this.imageElement.onmouseout = function() {

                     this.src = this.offImage.src;

                  };

               };

            }

            

            // set src of on state image after defining onload event handler

            // so cached images (that load instantly in IE) will trigger onload

            image.onImage.src = image.src.replace(/_off\./, '_on.');

         }

      }

   }

   rolloverInitialized = true;

}



// call rolloverInit when document finishes loading

if (isDefined(window.addEventListener)) {

   window.addEventListener('load', rolloverInit, false);

}

else if (isDefined(window.attachEvent)) {

   window.attachEvent('onload', rolloverInit);

}