<!DOCTYPE html>
<body>
<style>
textarea:valid {
    background-color: lime;
}
textarea:invalid {
    background-color: red;
}
</style>
<script src="../resources/runner.js"></script>
<textarea maxlength=2147483647 id="container"></textarea>
<script>
var container = document.getElementById('container');
container.focus();
PerfTestRunner.measureRunsPerSecond({run: function() {
    for (var i = 0; i < 500; ++i)
        document.execCommand('insertText', false, 'A quick brown fox jumps over the lazy dog.\n');
    container.value = '';
}});
</script>
</body>