title: Javascript: event.preventDefault() does not work for Japanese IME
body: <p>I want to create a text input which does not allowed to input any character (same as disabled input, but the mouse cursor still shown)</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function loadPage() {
    const el = document.getElementById('input-id');
    el.addEventListener('keydown', (event) =&gt; {
          event.preventDefault();
    });
  }
  loadPage();</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;input maxlength="0" id="input-id"&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>The above code works fine for normal alphabet characters.
  However, when I use IME to type Japanese fullwidth character, it does not work (still can input character)</p>
  
  <p>Do you know where is the problem, and is there anyway to workaround?</p>