Reset form element

reset.js

/**
 * Resets the value of a given form `element` to that originally set in the HTML.
 * Allows for more targetted reset that a `form.reset()` as neither HTMLFieldsetElement
 * nor the specific form controls API have a `reset()` method.
 *
 * Form elements can be accessed through:
 * - `fieldset.elements` if your elements are wrapped within a fieldset
 * - `ancestorElement.querySelectorAll('input,textarea,select')` 
 * - `form.elements` if you need specific filtering over the form fields
 *
 * @param element {HTMLElement}
 * @return void
 */
function reset(element) {
  if (element instanceof HTMLInputElement) {
    if (element.type == 'checkbox' || element.type == 'radio') {
      element.checked = element.getAttribute('checked');
    } else {
      element.value = element.getAttribute('value');
    }
  } else if (element instanceof HTMLSelectElement) {
    element.value = (
      element.querySelector('[selected]') || element.options[0]
    ).value;
  } else if (element instanceof HTMLTextAreaElement) {
    element.value = element.textContent;
  }
}