function valid(langue){

var reg = /^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]{2,}[.][a-zA-Z]{2,4}$/

if(langue=='fr'){
	var A_nom = "Le champs Nom est vide";
	var A_prenom = "Le champs Prénom est vide";
	var A_email = "Le champs Email est vide ou invalide";
	var A_msg = "Le champs Message est vide";
	}else{
	var A_nom = "Name field is empty";
	var A_prenom = "First name field is empty";
	var A_email = "Invalid email";
	var A_msg = "Message field is empty";
}
if(document.forms[0].nom.value == ""){
		alert(A_nom);
		document.forms[0].nom.focus();
		return false;
	}else if(document.forms[0].prenom.value == ""){
		alert(A_prenom);
		document.forms[0].prenom.focus();
		return false;
	}else if (reg.exec(document.forms[0].email.value)==null){
		alert(A_email);
		document.forms[0].email.focus();
		return false;
	}else if(document.forms[0].msg.value == ""){
		alert(A_msg);
		document.forms[0].msg.focus();
		return false;
	}else{
		SendMail(langue);
		return false;
	}
}