function randomImg(idImg,maxImg,arImg,idContainer)
{
    var randomNum = Math.random() * maxImg; 
    index = Math.round(randomNum);
    document.getElementById(idImg).src = arImg[index];
    if (idContainer != null)
    {
        document.getElementById(idContainer).style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + arImg[index] + "')";
    }
}
function randomBg(idImg,maxImg,arImg,bgOption)
{
    var randomNum = Math.random() * maxImg; 
    index = Math.round(randomNum); 
    document.getElementById(idImg).style.background = "url(" + arImg[index] + ") " + bgOption;
}