function MouseOver(img, ev) {
    var Xdoc, Xfen, Ydoc, Yfen, htDiv, lgDiv, dX, dY;
    var Ybulle;
    var el=document.getElementById("Bulle");

    //on affiche la boite de dialogue pour evaluer ses dimensions.
    if (el.style.display!="inline")
        el.style.display="inline";

    //hauteur et largeur de la bulle
    htDiv = el.offsetHeight;
    lgDiv = el.offsetWidth;

    //delta de la bulle sous la souris
    dY=10;
    dX=10;

    //position de la souris :
    Xfen = ev.clientX;
    Xdoc = Xfen + document.body.scrollLeft;

    Yfen = ev.clientY;
    Ydoc = Yfen + document.body.scrollTop;

    //position de la bulle dans la page :
    if ((Xfen + lgDiv + dX) > document.body.clientWidth)
        el.style.left = document.body.clientWidth + document.body.scrollLeft - lgDiv;
    else
        el.style.left = Xdoc + dX;

    if ((Yfen + htDiv + dY) > document.body.clientHeight) {
        Ybulle = document.body.clientHeight + document.body.scrollTop - htDiv-5;
        if (parseInt(Ybulle)>parseInt(Ydoc)) {
            el.style.top = Ybulle;
        }
        else {
            el.style.top = Ydoc - htDiv-dY;
        }
    }
    else {
        el.style.top = Ydoc + dY-5;
    }

    //contenu de la bulle :
    el.innerHTML = "<img src='" + img + "'>";
    //el.innerHTML = img;
    //el.innerHTML = " Xdoc= "+Xdoc+" px ; Ydoc= "+Ydoc+" px<br>";
    //el.innerHTML+= " Xfen= "+Xfen+" px ; Yfen= "+Yfen+" px";

}

function MouseOut() {
    //on cache la bulle
    document.getElementById("Bulle").style.display = "none";
}