var currBackground;
function initOoievaar(thisback){ 
    currBackground = thisback;
    showhide(currBackground);
}

function showhide(layer_ref) { 
    if (document.all) { //IS IE 4 or 5 (or 6 beta) 
        document.all.background1.style.display = "none"; 
        document.all.background2.style.display = "none"; 
        document.all.background3.style.display = "none"; 
        document.all.background4.style.display = "none"; 
        document.all.background5.style.display = "none"; 
        document.all.background6.style.display = "none"; 
        document.all.background7.style.display = "none"; 
        document.all.background8.style.display = "none";
        document.all.background9.style.display = "none";  

        eval( "document.all." + layer_ref + ".style.display = 'block'"); 
    } 
    if (document.layers) { //IS NETSCAPE 4 or below 
        document.layers['background1'].display = "none"; 
        document.layers['background2'].display = "none"; 
        document.layers['background3'].display = "none"; 
        document.layers['background4'].display = "none"; 
        document.layers['background5'].display = "none"; 
        document.layers['background6'].display = "none";
        document.layers['background7'].display = "none";
        document.layers['background8'].display = "none"; 
        document.layers['background9'].display = "none"; 

        document.layers[layer_ref].display = "block"; 
    } 
    if (document.getElementById &&!document.all) { 
        document.getElementById("background1").style.display = "none"; 
        document.getElementById("background2").style.display = "none"; 
        document.getElementById("background3").style.display = "none"; 
        document.getElementById("background4").style.display = "none"; 
        document.getElementById("background5").style.display = "none"; 
        document.getElementById("background6").style.display = "none"; 
        document.getElementById("background7").style.display = "none"; 
        document.getElementById("background8").style.display = "none"; 
        document.getElementById("background9").style.display = "none";

        hza = document.getElementById(layer_ref); 
        hza.style.display = "block"; 
    } 
}