function increase(img) { 
    theobject = img; 
    highlighting = setInterval("highlight(theobject)",40); 
} 
function decrease(img) { 
    clearInterval(highlighting) 
    if (img.style.MozOpacity) 
        img.style.MozOpacity = 0.5; 
    else if (img.filters) 
        img.filters.alpha.opacity = 40; 
} 
 
function highlight(img) { 
    if (img.style.MozOpacity < 1) 
        img.style.MozOpacity = parseFloat(img.style.MozOpacity) + 0.1; 
    else if (img.filters && img.filters.alpha.opacity < 100) 
        img.filters.alpha.opacity += 10; 
    else if (window.highlighting) 
        clearInterval(highlighting); 
}