function CheckRequiredFields(formobj){
 // Champs requis
 var fieldRequired = Array("lastName", "firstName", "email", "message");
 // Description des champs
 var fieldDescription = Array("Last name", "First name", "Your email", "Your message");
 // Message boite dialogue
 var alertMsg = "Please fill in the following feld(s):\n";
 
 var l_Msg = alertMsg.length;
 
 for (var i = 0; i < fieldRequired.length; i++){
  var obj = formobj.elements[fieldRequired[i]];
  if (obj){
   switch(obj.type){
   case "text":
   case "textarea":
    if (obj.value == "" || obj.value == null){
     alertMsg += " - " + fieldDescription[i] + "\n";
    }
    break;
   default:
    if (obj.value == "" || obj.value == null){
     alertMsg += " - " + fieldDescription[i] + "\n";
    }
   }
  }
 }

 // end checkboxes

 if (alertMsg.length == l_Msg){
  return true;
 }else{
  alert(alertMsg);
  return false;
 }
}
// END CHECKFORM

// submit once
function SubmitOnce(theform){
if (document.all||document.getElementById){
for (i=0;i<theform.length;i++){
var tempobj=theform.elements[i]
if(tempobj.type.toLowerCase()=="submit"||tempobj.type.toLowerCase()=="reset")
tempobj.disabled=true
}
}
}