//
// class;foreign language lessons
//

function setListeners(e) {

  var img_1a = './images/button1a.gif';
  var img_2a = './images/button2a.gif';
  var img_1b = './images/button1b.gif';
  var img_2b = './images/button2b.gif';

  // onMouseOver Event
  addListener($('reference'), 'mouseover', function(){$('reference').src = img_1b;}, false);
  addListener($('receipt'), 'mouseover', function(){$('receipt').src = img_2b;}, false);

  // onMouseOut Event
  addListener($('reference'), 'mouseout', function(){$('reference').src = img_1a;}, false);
  addListener($('receipt'), 'mouseout', function(){$('receipt').src = img_2a;}, false);

}

function addListener(elem, eventType, func, cap) {
  if(elem.addEventListener) {
    elem.addEventListener(eventType, func, cap);
  } else if(elem.attachEvent) {
    elem.attachEvent('on' + eventType, func);
  } else {
    return false;
  }
}

//
// body onload event
//
addListener(window, 'load', setListeners, false);