var W3CDOM = (document.createElement && document.getElementsByTagName);

var mouseOvers = new Array();
var mouseOuts = new Array();

window.onload = init;

function init()
{
    if (!W3CDOM) return;
    var imgs = getElementsByClass(document, 'rollover', 'img');
    for (var i=0;i<imgs.length;i++)
    {
        imgs[i].onmouseover = mouseGoesOver;
        imgs[i].onmouseout = mouseGoesOut;
        var suffix = imgs[i].src.substring(imgs[i].src.lastIndexOf('.'));
        mouseOuts[i] = new Image();
        mouseOuts[i].src = imgs[i].src;
        mouseOvers[i] = new Image();
        mouseOvers[i].src = imgs[i].src.substring(0,imgs[i].src.lastIndexOf('.')) + "2" + suffix;
        imgs[i].number = i;
    }
}

function mouseGoesOver()
{
    this.src = mouseOvers[this.number].src;
}

function mouseGoesOut()
{
    this.src = mouseOuts[this.number].src;
}



function getElementsByClass(node,searchClass,tag) 
{
 var classElements = new Array();
 var els = node.getElementsByTagName(tag);
 var elsLen = els.length;
 var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
 for (i = 0, j = 0; i < elsLen; i++) {
    if ( pattern.test(els[i].className) ) {
      classElements[j] = els[i];
      j++;
    }
  }
  return classElements;
}