Blend mode:multiply in Internet Explorer

For Internet Explorer, Canvas blending modes are "under consideration".

https://developer.microsoft.com/en-us/microsoft-edge/platform/status/mixblendmode/?q=blend

Until blends are implemented in IE, you can roll-your-own multiply filter:

function multiply(R, G, B) {
  var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  var data = imgData.data;

  for (var i = 0; i < data.length; i += 4) {
    data[i    ] = R * data[i    ] / 255;
    data[i + 1] = G * data[i + 1] / 255;
    data[i + 2] = B * data[i + 2] / 255;
  }

  ctx.putImageData(imgData, 0, 0);
}

And this multiply image filter is cross-browser compatible too.

Here I found a fully css solution:

https://teamtreehouse.com/community/fallback-for-css-blending-modes

which is:

<!--[if IE]>
  <style>
          .yourTargetClass:before {
               content: "";
               position: absolute;
               height: 100%;
               width: 100%;
               background: rgba(10, 36, 54, 0.9); /* THIS IS WHAT EVER OVERLAY COLOUR YOU WANT */
           }
   </style>