<style>
textarea {
  width: 40px;
  height: 500px;
}
</style>
<pre>
1. Move caret to the end of the editable content.
2. Hit enter-backspace-enter combo.
PASS if caret moves. 
</pre>
<textarea id=focus_this>ABC ABC ABC</textarea>
<pre id=result></pre>
<script>
if (window.testRunner)
  testRunner.dumpAsText();
focus_this.focus();
document.execCommand('selectAll', false, null);
document.getSelection().collapseToEnd();
document.execCommand('insertText', false, "\n");
window.getSelection().modify("extend", "backward", "character");
document.execCommand('forwardDelete');
document.execCommand('insertText', false, "\nPASS");
result.innerText = focus_this.value;
</script>
