title: Typescript how to tell that element is checkbox, so element.checked is not red underlined
body: <p>I am checking for input type of some element, fe checkbox in TS. Now I am sure that I have element that is checkbox, so this element should have property checked. But if I simply do </p>
  
  <pre><code>element: HTMLElement
  if (element.InputType.toLowerCase() == "checkbox"){
      element.checked = true;
  }
  </code></pre>
  
  <p>than it is working, but element.checked is red underlined. I think that I simply have to retype from HTMLElement to something like CheckboxElement, but did not find anything suitable for this conversion. How to get rid of this ? I have facing this also in case of element.value</p>