var originalSrc = '';
function rollOn(linkObj)
{
  if (linkObj.hasChildNodes && linkObj.firstChild.nodeName.toLowerCase() == 'img') {
    originalSrc = linkObj.firstChild.src
    switch (linkObj.firstChild.className) {
      case 'addEvent':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_addevent_b.jpg';
        break;
      case 'addReview':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_addReview_b.jpg';
        break;
      case 'archives':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_archives_b.jpg';
        break;
      case 'idCard':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_card_b.jpg';
        break;
      case 'localLaws':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_laws_b.jpg';
        break;
      case 'toTop':
        linkObj.firstChild.src = 'http://www.fresnocannabisclubs.com/images/button_top_b.jpg';
        break;
      default:
			  alert('There is no case for this image.');
    }
  }
}

function rollOff(linkObj)
{
  if (linkObj.hasChildNodes && linkObj.firstChild.nodeName.toLowerCase() == 'img')
    linkObj.firstChild.src = originalSrc;
}