<body>
<style>
.editable {
  -webkit-user-modify: read-write-plaintext-only;
  border: 2px solid blue;
}
</style>
<div class="editable"></div>
<script>
if (window.eventSender) {
    var control = document.querySelector('.editable');
    control.focus();
    eventSender.keyDown('a');
    eventSender.keyDown('b');
}
if (window.testRunner)
    testRunner.dumpAsText();
</script>
</body>