title: How to disappear canvas text when click on button
body: <p>How can I disappear the text "?" in the canvas when I click on a button?</p>
  
  <p>Heres the link to my code:  <a href="https://codepen.io/firassyazwani/pen/NWWKMGK" rel="nofollow noreferrer">https://codepen.io/firassyazwani/pen/NWWKMGK</a></p>
  
  <pre><code>function draw() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    ctx.fillStyle = '#FFFF33';
    ctx.fillRect(rect.x, rect.y, rect.w, rect.h);
    if (currentHandle) {
      var posHandle = point(0, 0);
      switch (currentHandle) {
        case 'topright':
          posHandle.x = rect.x + rect.w;
          posHandle.y = rect.y;
          break;
        case 'bottomright':
          posHandle.x = rect.x + rect.w;
          posHandle.y = rect.y + rect.h;
          break;
      }
      ctx.globalCompositeOperation = 'xor';
      ctx.beginPath();
      ctx.arc(posHandle.x, posHandle.y, handlesSize, 0, 2 * Math.PI);
      ctx.fill();
      ctx.globalCompositeOperation = 'source-over';
    }
  </code></pre>