<!DOCTYPE html>
<html>
<head>
<title>This tests that selection gaps can be painted on subpixel position.</title>
<style>
  ::selection {
    background: rgba(255, 0, 0, 0.9);
  }

  div {
    font-size: 16px;
    font-family: 'Ahem';
    height: 20px;
  }

</style>
</head>
<body>
<p id="container"></p>
<script>
  var container = document.getElementById("container");
  fontSize = 16;
  margin = 0;
  for (i = 0; i <= 20; ++i) {
    var e = document.createElement("div");
    e.innerHTML = "&nbsp";
    e.style.fontSize = fontSize + "px";
    e.style.margin = margin + "px";
    container.appendChild(e);
    fontSize+=0.3;
    margin+=0.5;
  }

  var range = document.createRange(); 
  range.selectNode(document.getElementById("container")); 
  window.getSelection().addRange(range);
</script>
</body>
</html>