web-canvas-overlay.htm

<style>
        #container {
          position: relative;
        }
     
        #imageCanvas {
          position: relative;
          z-index: 1;
        }
     
        #overlay {
          position: absolute;
          top: 0;
          left: 0;
          z-index: 2
        }
     
      </style>
 
<div id="container">
        <canvas id="imageCanvas"> </canvas>
        <canvas id="overlay"></canvas>
</div>