<!DOCTYPE html>
<style>
.box {
  width: 200px;
  height: 200px;
  margin: 20px;
  background-color: green;
  filter: url(#composite);
}
</style>
<div class="box"></div>
<svg width="0" height="0">
  <filter id="composite" x="-0.5" y="-0.5" width="2" height="2">
    <feFlood x="100" y="100" width="200" height="200" flood-color="blue"/>
    <feComposite operator="atop" in="SourceGraphic"/>
  </filter>
</svg>