function show_page(index) {

div = document.getElementById("page_"+index);

divs = document.getElementById("contenu").getElementsByTagName("div");
for (i=0; i < divs.length; i++) {
	if (divs[i].className == "navig") {
		divs[i].style.display = 'none';
		}
	}

// on affiche le nouveau
div.style.display = 'block';

return 0;
}