function popup(theme) {
	var jax = null; 
	if (window.XMLHttpRequest) {
		jax = new XMLHttpRequest();
	} else if (window.ActiveXObject) {
		jax = new ActiveXObject("Microsoft.XMLHTTP");
	}
	var divpopup = document.getElementById("popup");
	var divpage = document.getElementById("pageentiere");
	theme = escape(theme);
	var m = new Date();
	var t = m.getTime();
	jax.open("GET", "/bin/ajax_popup.php?theme=" + theme + "&t=" + t, true); 
	jax.onreadystatechange = function() {
		if (jax.readyState == 4) {
			if (jax.responseText != "") {
				if (jax.responseText != "bad") {
					var depart = document.documentElement.scrollTop;
					if (! depart) {  
						depart = document.body.scrollTop;
					}
					if (! depart) {  
						depart = window.pageXOffset;
					}
					if (! depart) depart = 0;
					var	hauteur = screen.availHeight;
					var largeur = screen.availWidth;
					divpopup.style.display = "inline";
					divpopup.style.left = ((largeur - 550) / 2) + "px";
					divpopup.style.top = (depart + ((hauteur - 400) / 2)) + "px";
					divpopup.innerHTML = jax.responseText;
					divpopup.style.visibility = "visible";
					divpage.className='opaque';
				}
			}
		}
	} 
	jax.send(null);
}

function unpopup() {
	var divpopup = document.getElementById("popup");
	var divpage = document.getElementById("pageentiere");
	divpopup.style.visibility = "hidden";
	divpopup.style.display = "none";
	divpage.className='clair';
}