function checkContactForm(lang)
	{
		document.getElementById("formSuccessMessage").style.display = "none";
		document.getElementById("formErrorMessage").style.display = "none";
		
		var messageMinLenght = 20;
		var messageMaxLenght = 500;
			
		var errMess = "";
		var allOk = true;
		
		var lastName = document.getElementById('lastname').value;
		var firstName = document.getElementById('firstname').value;
		
		var mail = document.getElementById('email').value;
		var mailFilter = /^([a-zA-Z0-9-_.])+@{1}([a-zA-Z0-9])+.{1}([a-zA-Z0-9]){2,4}$/;
		
		var message = document.getElementById('message').value;
		
		if (lastName.length < 3) { errMess += "<li>Veuillez renseigner votre nom.</li>"; }
		if (firstName.length < 3) { errMess += "<li>Veuillez renseigner votre pr&eacute;nom.</li>"; }
		if (!mailFilter.test(mail)) { errMess += "<li>Veuillez renseigner un email valide.</li>"; }
		if (message.length < messageMinLenght || message.length > messageMaxLenght) { errMess += "<li>Veuilez entrer un message entre "+messageMinLenght+" et "+messageMaxLenght+" caract&egrave;res.</li>"; }
		
		if(errMess === "") { allOk = true; }
		else { allOk = false; }
		
		if(allOk)
			{
				document.getElementById("formSuccessMessage").style.display = "block";
				document.getElementById("formSuccessMessage").innerHTML = "Message envoy&eacute;";
				
				//If fonction mail ...
				
			}
		else
			{
				document.getElementById("formErrorMessage").style.display = "block";
				document.getElementById("formErrorMessage").innerHTML = '<ul>'+errMess+"</ul>";
			}	
	}