Regex Javascript.js

function validateContact() {
  // Baguhin mo lang onti to
  var contact = document.getElementById('contact').value;
  var contactLength = contact.length;
 
  // Dagdag mo tong variable na to, regex tester
  var contactIsDigit = /^\d+$/.test(contact);
  
  // Tapos may last na condition
  if((contactLength == 7 || contactLength == 11) && contactIsDigit) {
    submitButton.disabled = false;
  } else {
    alert('Invalid number length');
    submitButton.disabled = true;
  }
}