<!DOCTYPE html>
<meta charset=utf-8>
<title>The output element</title>
<link rel="author" title="Denis Ah-Kang" href="mailto:denis@w3.org">
<link rel=help href="https://html.spec.whatwg.org/multipage/#the-output-element">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<output id=output></output>
<script>
  var output = document.getElementById("output");

  test(function(){
    assert_equals(output.type, "output", "type must return the string 'output'");
    assert_equals(output.textContent, "", "textContent is empty");
    assert_equals(output.value, "", "value should be empty");
    assert_equals(output.defaultValue, "", "defaultValue should be empty");

    output.textContent="5";
    assert_equals(output.value, "5", "textContent is set to 5: value is updated");
    assert_equals(output.textContent, "5", "textContent is set to 5");
    assert_equals(output.defaultValue, "5", "textContent is set to 5: defaultValue is updated");

    output.defaultValue="10"; // value mode flag is in "default" mode. Setting defaultValue should set textContent as well
    assert_equals(output.value, "10", "defaultValue is set to 10: value is updated");
    assert_equals(output.textContent, "10", "defaultValue is set to 10: textContent is updated");
    assert_equals(output.defaultValue, "10", "defaultValue is set to 10");

    output.value="20";  // set the value mode flag to "value": default value remains unchanged
    assert_equals(output.value, "20", "value is set to 20");
    assert_equals(output.textContent, "20", "value is set to 20: textContent is updated");
    assert_equals(output.defaultValue, "10", "value is set to 20: defaultValue remains unchanged");

    output.defaultValue="15"; // value mode flag is in "value" mode. textContent remains unchanged when setting defaultValue
    assert_equals(output.value, "20", "defaultValue is set to 15: value remains unchanged");
    assert_equals(output.textContent, "20", "defaultValue is set to 15: textContent remains unchanged");
    assert_equals(output.defaultValue, "15", "defaultValue is set to 15");
  }, "output value and defaultValue");
</script>