function clearHelpText(elem) {
  if (elem.defaultValue == elem.value) elem.value = "";
}

function restoreHelpText(elem) {
  if (elem.id == "contact-name" && elem.value == "") elem.value = "Name";
  if (elem.id == "phone" && elem.value == "") elem.value = "Phone number";
  if (elem.id == "email" && elem.value == "") elem.value = "Email address";
}