Function isDisabled

aspnet-samples/AspNetForm/Scripts/bootstrap.js:187–198

    return elementIsVisible;
  };
  const isDisabled = element => {
    if (!element || element.nodeType !== Node.ELEMENT_NODE) {
      return true;
    }
    if (element.classList.contains('disabled')) {
      return true;
    }
    if (typeof element.disabled !== 'undefined') {
      return element.disabled;
    }
    return element.hasAttribute('disabled') && element.getAttribute('disabled') !== 'false';
  };
  const findShadowRoot = element => {
    if (!document.documentElement.attachShadow) {
      return null;