function rollover(object,preload)
{
    if (object.src)
    {
        image = object.src;
        imageDot = image.lastIndexOf('.');
        if (imageDot > -1)
        {
            imageName = image.substr(0,imageDot);
            imageExt = image.substr(imageDot+1);
            if (preload) object = new Image();
            if (imageName.substr(imageName.length-5)=='-over')
                imageName = imageName.substr(0, imageName.length-5);
            else
                imageName += '-over';
            object.src = imageName + '.' + imageExt;
        }
    }
}