As Thanos making a snap with the Infinite Gauntlet, half the heros vanish to dust. As using the time stone, people come back.

The procedures:

1. Click the Gauntlet button, and display animation to make a snap, and play audio file;
2. Select half heros by random, the random method is to resort members array;

arr.sort(function() {
  return 0.5 - Math.random();
});

3. Make selected item to dust

• 3.1 use html2canvas library to convert dom to a canvas image
• 3.2 split the canvas images into many pieces by pixel, function generateFrames()
• 3.3 create a container which has the same size and position as the converted dom
• 3.4 appendChild to the container with the pieces
• 3.5 rotate random degrees and translate random pixel for each piece, which shows the dust animation
• 3.6 set converted dom item to be invisible and finish the SNAP action

4. Reverse time to bring heros back by adjusting the visibility of converted dom items

Why use a nodejs express server?

A static html file will show errors with "Unable to get image data from canvas because the canvas has been tainted by cross-origin data", even if I set allowTaint to be true.