CSS

mask image css

#masked {
  width: 100px;
  height: 100px;
  background-color: #8cffa0;
  -webkit-mask-image: url(https://mdn.mozillademos.org/files/12676/star.svg);
  mask-image: url(https://mdn.mozillademos.org/files/12676/star.svg);
}

css masking

.target {
  mask: url(#c1) luminance;
}

.anothertarget {
  mask: url(resources.svg#c1) 50px 30px/10px 10px repeat-x exclude;
}

mask image css

<div id="masked"></div>