var imgBackGroundArray = new Array();
imgBackGroundArray[0] = "images/Welcome/Welcome1.jpg";
imgBackGroundArray[1] = "images/Welcome/Welcome2.jpg";
imgBackGroundArray[2] = "images/Welcome/Welcome3.jpg";
imgBackGroundArray[3] = "";

function changeBackground(whichImage)
{
    if (document.body)
    {
        document.body.style.backgroundColor="Black";
        document.bgColor="Black";
        document.body.style.backgroundImage = "url(" + imgBackGroundArray[whichImage] + ")";
        //document.body.style.backgroundImage = imgBackGroundArray[whichImage];
        
        if (whichImage== 3)
        {
            document.body.style.backgroundColor="White";
            document.bgColor="White";

            document.body.style.backgroundColor="Black";
            document.bgColor="Black";
        }
    }
}