function afficher_concours(url) {
	var xhr_object = null;
	if(window.XMLHttpRequest) {
		// Firefox et autres navigateurs supportant le constructeur XMLHttpRequest()
		xhr_object = new XMLHttpRequest();
	} else if(window.ActiveXObject) {
		// Internet Explorer
		xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
	} else { 
		// XMLHttpRequest non supporté par le navigateur
		alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest...");
		return;
	}

xhr_object.onreadystatechange = function() {	
	if (xhr_object.readyState == 4) {
		var reponse=xhr_object.responseText;
document.getElementById("contenupage").innerHTML = reponse;
}
}
xhr_object.open("POST", url, true);
xhr_object.setRequestHeader('Content-Type','application/x-www-form-urlencoded');

reponse1=document.forms.concours.elements['textequestion1'].value;
reponse1=escape(reponse1);
reponse2=document.forms.concours.elements['textequestion2'].value;
reponse2=escape(reponse2);
reponse3=document.forms.concours.elements['textequestion3'].value;
reponse3=escape(reponse3);
reponsecase1=document.forms.concours.elements['textequestioncase1'].value;
reponsecase1=escape(reponsecase1);
reponsecase2=document.forms.concours.elements['textequestioncase2'].value;
reponsecase2=escape(reponsecase2);


xhr_object.send("reponse1="+reponse1+"&reponse2="+reponse2+"&reponse3="+reponse3+"&reponsecase1="+reponsecase1+"&reponsecase2="+reponsecase2);
	
}