html/rendering/widgets/field-sizing-select.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-ui-4/#field-sizing">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<style>
.disable-default {
  field-sizing: content;
}
</style>
<div id="container"></div>
<script>
const container = document.querySelector('#container');
const DISABLE = 'class="disable-default"';

// Tests for drop-down box ====================================================

test(() => {
  const s = '<select>><option>1<option>quick brown<option>fox</select>';
  container.innerHTML = s + s;
  container.lastElementChild.style.fieldSizing = 'content';
  const widthForContent1 = container.lastElementChild.offsetWidth;
  assert_greater_than(container.firstElementChild.offsetWidth,
                      widthForContent1);
  container.lastElementChild.selectedIndex = 1;
  const widthForContentQuickBrown = container.lastElementChild.offsetWidth;
  assert_greater_than(widthForContentQuickBrown, widthForContent1);
}, 'dropdown: The width should depend on the selected OPTION');

test(() => {
  container.innerHTML = '<select><option>foo<option>quick brown fox</select>';
  const select = container.firstElementChild;
  const initialWidth = select.offsetWidth;
  select.style.fieldSizing = 'content';
  assert_less_than(select.offsetWidth, initialWidth);
  select.style.fieldSizing = 'fixed';
  assert_equals(select.offsetWidth, initialWidth);
}, 'dropdown: Change the field-sizing value dynamically');

// Tests for list box =========================================================

// Some paltforms don't support list box rendering.
container.innerHTML = '<select></select><select multiple></select>';
if (container.firstElementChild.offsetHeight != container.lastElementChild.offsetHeight) {

  test(() => {
    container.innerHTML = `<select multiple><option>fox</select>` +
                          `<select multiple ${DISABLE}><option>fox</select>`;
    const former = container.firstElementChild;
    const latter = container.lastElementChild;
    const widthForOneItem = latter.offsetWidth;
    const heightForOneItem = latter.offsetHeight;
    assert_equals(former.offsetWidth, widthForOneItem);
    assert_greater_than(former.offsetHeight, heightForOneItem);

    latter.add(new Option('quick brown'));
    assert_greater_than(latter.offsetWidth, widthForOneItem);
    assert_greater_than(latter.offsetHeight, heightForOneItem);
  }, 'listbox: The size depend on the content');

  test(() => {
    container.innerHTML = `<select size="4"></select><select size="4" ${DISABLE}></select>`;
    const former = container.firstElementChild;
    const latter = container.lastElementChild;
    const widthForZeroItem = latter.offsetWidth;
    const heightForZeroItem = latter.offsetHeight;
    assert_equals(former.offsetWidth, widthForZeroItem);
    assert_greater_than(former.offsetHeight, heightForZeroItem);

    latter.add(new Option('quick brown'));
    assert_greater_than(latter.offsetWidth, widthForZeroItem);
    assert_greater_than(latter.offsetHeight, heightForZeroItem);
  }, 'listbox: The size attribute value is ignored');

  test(() => {
    container.innerHTML = '<select multiple><option>foo<option>quick brown fox</select>';
    const select = container.firstElementChild;
    const initialHeight = select.offsetHeight;
    select.style.fieldSizing = 'content';
    assert_less_than(select.offsetHeight, initialHeight);
    select.style.fieldSizing = 'fixed';
    assert_equals(select.offsetHeight, initialHeight);
  }, 'listbox: Change the field-sizing value dynamically');

}
</script>
</body>