function preload_images(prefix,total,ext){
    var i;
    var inter = "on_0";
    var tTab = new Array();
    for(i=1; i<=total; i++){
        inter = (i>9)?"on_":"on_0";
        tTab[i] = new Image();
		tTab[i].src = prefix + inter + i +"."+ ext;
    }
}

function ouvrir_div(num){
    document.getElementById("DIV"+num).style.display = (document.getElementById("DIV"+num).style.display == "none") ? "block" : "none";
}