// JavaScript Document
function checkFields() {
missinginfo = "";

if(document.form.prenom.value == "") {
missinginfo += "\n     -  Prénom";
}

if(document.form.nom.value == "") {
missinginfo += "\n     -  Nom";
}

if ((document.form.email.value == "") || 
(document.form.email.value.indexOf('@') == -1) || 
(document.form.email.value.indexOf('.') == -1)) {
missinginfo += "\n     -  E-mail";
}

if(document.form.message.value == "") {
missinginfo += "\n     -  Message";
}

if (missinginfo != "") {
missinginfo ="_____________________________\n" +
"Les champs marqués d un * doivent obligatoirement etre renseignés!:\n" +
missinginfo + "\n_____________________________" +
"\n";
alert(missinginfo);
return false;
}
else return true;
}