function FRK_ROLLOVER(){
  if(!document.getElementsByTagName) return false;

  var cn = document.all && !window.opera ? 'className' : 'class';
  var key = '_ov', cname = 'ro';
  var overChk1 = new RegExp('_ov' + "(\.[a-z]+)$");
  var overChk2 = new RegExp('_op' + "(\.[a-z]+)$");
  var elems = document.getElementsByTagName('img');
  for(var i=0; i<elems.length; i++){
    elem = elems[i];
    if(cname == elem.getAttribute(cn)){
      var outSrc;
      var preloadImg = new Image();
      var src = elem.getAttribute('src');
      if(!src.match(overChk1) || !src.match(overChk2)){
        preloadImg.src = src.replace(/(\.[a-z]+)$/, key + "$1");
        elem.onmouseover = function(){
          outSrc = this.getAttribute('src');
          var overSrc = outSrc.replace(/(\.[a-z]+)$/, key + "$1");
          if(overSrc) this.src = overSrc;
          return false;
        };
        elem.onmouseout = function(){
          if(outSrc) this.src = outSrc;
          return false;
        };
      }
    }
  }
}

function FRK_LOAD(func){
  if(window.addEventListener) window.addEventListener('load', func, false);
  else if(window.attachEvent) window.attachEvent('onload', func);
  else window.onload = function(){func();}
}

FRK_LOAD(FRK_ROLLOVER);