function resize() {
    var htmlheight = document.body.scrollHeight;
    var windowHeight = document.documentElement.clientHeight;
    var windowWidth = document.documentElement.clientWidth;

    var backgroundAnimation = document.getElementById("backgroundAnimation");
    var dynamicContent = document.getElementById("dynamicContent");



    var dynamicContentHeight = windowHeight - 278 - (2 * 27); //27 is hoogte van grunge header/footer afbeelding
    if (dynamicContentHeight < 0) dynamicContentHeight = 0;


    backgroundAnimation.style.height = windowHeight + "px";
    backgroundAnimation.style.width = windowWidth + "px";
    if (dynamicContentHeight < dynamicContent.clientHeight) {
        dynamicContent.style.height = dynamicContentHeight + "px";
        dynamicContent.style.overflowY = "scroll";
    }




}