function open_chat() {
				   if (document.getElementById("chat").age.value == 0)
				   {
				   alert ("Et ton âge alors ?");
				   }
				   if (document.getElementById("chat").ville.value == "SDF")
				   {
				   alert ("Pas de région ?");
				   }
				   if (document.getElementById("chat").pseudo.value.length == 0) 
				   { 
				   alert ("Tu dois spécifier un pseudo"); 
				   }
				   else{ 
				    pseudo = document.getElementById("chat").pseudo.value ;
				    age = document.getElementById("chat").age.value ;
				    if (document.getElementById("chat").sexe[0].checked==true)
						{ sexe = "h"; }
						else { sexe = "f"; }
				    ville = document.getElementById("chat").ville.value ;
				    if (screen.width <= 800) {
					applet_size = 1
				    }
				    else {
					applet_size = 2
				    }
					if (applet_size == 1) {
					    window_app = "toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=800,height=550";
					} else {
					    window_app = "toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,width=920,height=620";
					}
				  url="http://www.loisirados.com/chat-ado/web/webdialogue.php?nick="+escape(pseudo)+"&age="+escape(age)+"&sexe="+escape(sexe)+"&ville="+escape(ville)+"&salon=web-ados.com&mainbg=FFFFFF";
				  window.open(url, "_blank", window_app);
				  return;
				 }
				}