chromium/third_party/blink/renderer/core/testing/data/textbox.html

<!DOCTYPE html>
<html>
<head>
  <style>
    html {
      font: 10px Ahem;
      -webkit-font-smoothing: none;
      margin: 0px;
    }
    textarea {
      font: 10px Ahem;
      -webkit-font-smoothing: none;
      margin: 0px;
      position: absolute;
      left: 200px;
      top: 250px;
    }

  </style>
</head>
<body>
<textarea id='target' class="text" type='text' rows="3" cols="20">
First Line
Second Text Row
</textarea>
<script>
    function selectRange() {
        var text = document.getElementById('target');
        text.focus();
        text.setSelectionRange(1, 3);
    }
</script>
</body>
</html>