ladybird/Tests/LibWeb/Text/input/UIEvents/KeyEvent-cancelled.html

<input id="input" />
<script src="../include.js"></script>
<script>
    test(() => {
        let input = document.getElementById("input");
        input.value = "You can't change me!";

        input.focus();
        input.select();

        let shouldCancelKeyDown = false;
        let shouldCancelKeyPress = false;

        input.addEventListener("keydown", e => {
            println(`keydown ${e.key}`);

            if (shouldCancelKeyDown) {
                println("cancel keydown");
                e.preventDefault();
            }
        });
        input.addEventListener("keypress", e => {
            println(`keypress ${e.key}`);

            if (shouldCancelKeyPress) {
                println("cancel keypress");
                e.preventDefault();
            }
        });

        shouldCancelKeyDown = true;
        shouldCancelKeyPress = false;
        internals.sendText(input, "A");
        println(input.value);

        shouldCancelKeyDown = false;
        shouldCancelKeyPress = true;
        internals.sendText(input, "B");
        println(input.value);

        shouldCancelKeyDown = false;
        shouldCancelKeyPress = false;
        internals.sendText(input, "C");
        println(input.value);
    });
</script>