title: How can I check the checkbox with mousedown event?
body: <p>I have the following code:</p>
  
  <pre><code>checkbox.addEventListener('mousedown', function () {
      if (!this.checked) {
          this.checked = true;
      }
  });
  </code></pre>
  
  <p>It should turn on the checkbox when mouse button is down.
  And it works perfectly but when I release the button, the checkbox turns back off. How can i fix this?</p>