function checkForm() {
name = document.getElementById("name").value;
  email = document.getElementById("email").value;
  comment = document.getElementById("comment").value;
  amount = document.getElementById("amount").value;
  
  if (name == "") {
  hideAllErrors();
document.getElementById("nameError").style.display = "inline";
document.getElementById("name").select();
document.getElementById("name").focus();
  return false;
  } else if (email == "") {
hideAllErrors();
document.getElementById("emailError").style.display = "inline";
document.getElementById("email").select();
document.getElementById("email").focus();
  return false;
  } else if (comment == "") {
hideAllErrors();
document.getElementById("commentError").style.display = "inline";
document.getElementById("comment").select();
document.getElementById("comment").focus();
  return false;
  } else if (amount == "") {
hideAllErrors();
document.getElementById("amountError").style.display = "inline";
document.getElementById("amount").select();
document.getElementById("amount").focus();
  return false;
  }
  return true;
  }
 
  function hideAllErrors() {
document.getElementById("nameError").style.display = "none"
document.getElementById("emailError").style.display = "none"
document.getElementById("commentError").style.display = "none"
document.getElementById("amountError").style.display = "none"
  }