function validateCallbackData() {

 var check = true;


  var lastname  = document.getElementById("lastname").value;
  var phone     = document.getElementById("phone").value;    
  var email     = document.getElementById("email").value; //not mandatory field
  var captcha   = document.getElementById("captchaResult")
  var inquiry   = document.getElementById("inquiry").value;


  
  if(lastname && lastname.length < 3 ){
      document.getElementById("error_lastname").style.visibility = "visible";
      check = false;
  }
  
  if(phone && phone.length < 3) {
      document.getElementById("error_phone").style.visiblity = "visible";      
      check = false;
  }
  
  
  if(email && !email.match(/^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$/)) {
    document.getElementById("error_email").style.visibility = "visible";
    check = false;
   }
   
   
   

  return check;
  }

function unsetErrorMessage(m) {

     if(document.getElementById(m) != null)
     	document.getElementById(m).style.visibility = "hidden";
  }