// == functie voor overview rollovers =================

function ON(num) {
	document.getElementById("table_bg_" + num).style.background='url(media/imgs/overview_bg_on.gif)';
};

function OFF(num) {
	document.getElementById("table_bg_" + num).style.background='url(media/imgs/nix.gif)';
};


// == roll over + preload ===============================

var flag = false;

function imageLoad() {  // called with onLoad()
    if (document.images) {
        img1on = new Image(); img1on.src = "media/imgs/b_1_on.gif";
        img2on = new Image(); img2on.src = "media/imgs/b_2_on.gif";
        img3on = new Image(); img3on.src = "media/imgs/b_3_on.gif";
        img4on = new Image(); img4on.src = "media/imgs/b_4_on.gif";
        return (flag = true);  // set the flag and let the function know know it can work
    }
}

if (document.images) {   // load the off images in the normal way
    img1off = new Image(); img1off.src = "media/imgs/b_1_off.gif";
    img2off = new Image(); img2off.src = "media/imgs/b_2_off.gif";
    img3off = new Image(); img3off.src = "media/imgs/b_3_off.gif";
    img4off = new Image(); img4off.src = "media/imgs/b_4_off.gif";
}


function rollIn(imgName) {
    if (document.images && (flag == true)) {
        document[imgName].src = eval(imgName + "on.src");
    }
}

function rollOut(imgName) {  // the normal onMouseOut function
    if (document.images){
        document[imgName].src = eval(imgName + "off.src");
    }
}