function rotateBackground(imageID) {
    var totalImages = 4;
    var newID = imageID + 1;
    if (newID > totalImages)
        newID = 1;
    document.getElementById("header_bg"+imageID+"x").style.visibility = "hidden";
    document.getElementById("header_bg"+imageID).style.visibility = "hidden";
    for (var tempID = 1; tempID < totalImages+1; tempID++) {
        document.getElementById("header_bg"+tempID+"x").style.display = "none";
        document.getElementById("header_bg"+tempID).style.display = "none";
    }
    document.getElementById("header_bg"+imageID+"x").style.display = "block";
    document.getElementById("header_bg"+imageID).style.display = "block";
    document.getElementById("header_bg"+imageID+"x").style.visibility = "visible";
    document.getElementById("header_bg"+imageID).style.visibility = "visible";
    var timingEvent = setTimeout("rotateBackground("+newID+")",7000);
}
rotateBackground(1);