function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}	

function validateForm(theForm)
{
	var elArr = theForm.elements; 
	for(var i = 0; i < elArr.length; i++)
	{
		elArr[i].className = ""; 

		if(((elArr[i].name == "prenom") || (elArr[i].name == "nom") || (elArr[i].name == "email") || (elArr[i].name == "secteur") || (elArr[i].name == "telephone")) && IsEmpty(elArr[i])) 
		{ 
			alert(elArr[i].name + ": ce champs est obligatoire");
			//elArr[i].select();
			//elArr[i].focus(); 
			//elArr[i].className = "textboxError"; 
			return false;
		}
	} 

	return true;
}