function checkForm() {
  ContactName = document.getElementById("ContactName").value;
  Phone = document.getElementById("Phone").value;
  Email = document.getElementById("Email").value;
 
  if (ContactName == "") {
  hideAllErrors();
document.getElementById("ContactNameError").style.display = "inline";
document.getElementById("ContactName").select();
document.getElementById("ContactName").focus();
  return false;
  
  } else if (Phone == "") {
hideAllErrors();
document.getElementById("PhoneError").style.display = "inline";
document.getElementById("Phone").select();
document.getElementById("Phone").focus();
  return false;
  
  } else if (Email == "") {
hideAllErrors();
document.getElementById("EmailError").style.display = "inline";
document.getElementById("Email").select();
document.getElementById("Email").focus();
  return false;
  }
  return true;
  }
 
  function hideAllErrors() {
document.getElementById("ContactNameError").style.display = "none"
document.getElementById("PhoneError").style.display = "none"
document.getElementById("EmailError").style.display = "none"
  }