function cOnPrinc(td){
    if(document.getElementById||(document.all && !(document.getElementById))){
        td.className="menu_princ menu_princ_hover";
    }
}
function cOutPrinc(td){
    if(document.getElementById||(document.all && !(document.getElementById))){
        td.className="menu_princ menu_princ_pas_hover";
    }
}

function GotoUrl(url_cible)
{
   window.location.href = url_cible;
}