var boite = document.getElementById("reservation_liligo");

boite.style.border = "0";
boite.style.width = "310px";
boite.style.marginLeft = "0px";
boite.innerHTML = '<iframe name="resa" id="resa" src="http://www.liligo.fr/msn/ete/" frameborder="0" width="311" height="320" hspace="0" vspace="0" marginheight="0" marginwidth="0" scrolling="no"></iframe>';