function rolloversInit(className) {
    if (!document.getElementsByTagName)
        return;
        
    var rollovers = document.getElementsByTagName('img');
    for (var i = 0; i < rollovers.length; i++) {
        var img = rollovers[i];
        if (img.className && (' ' + img.className + ' ').indexOf(className) != -1) {
            img.onmouseover = rolloverMouseOver;
            img.onmouseout = rolloverMouseOut;
        }
    }
}

function findTarget(e, tagName) {
    var target;
    
    if (window.event && window.event.srcElement) {
        target = window.event.srcElement;
    } else if (e && e.target) {
        target = e.target;
    }
    
    if (!target) return null;
    
    while (target != document.body && target.nodeName.toLowerCase() != tagName)
        target = target.parentNode;
        
    if (target.nodeName.toLowerCase() != tagName)
        return null;
        
    return target;
}                       

function rolloverMouseOver(e) {
    var target = findTarget(e, 'img');
    if (!target) return;
    
    target.src = target.src.replace(/(\.[^.]+)$/, '-ovr$1');
}                

function rolloverMouseOut(e) {
    var target = findTarget(e, 'img');
    if (!target) return;
    
    target.src = target.src.replace(/-ovr(\.[^.]+)$/, '$1'); 
}

addLoadEvent(rolloversInit);