HTML

Living Standard — Last Updated 5 May 2025

1. 1. 4.11 対話的な要素
      1. 4.11.1 details要素
      2. 4.11.2 summary要素
      3. 4.11.3 コマンド
         1. 4.11.3.1 ファセット
         2. 4.11.3.2 Using the a element to define a command
         3. 4.11.3.3 Using the button element to define a command
         4. 4.11.3.4 Using the input element to define a command
         5. 4.11.3.5 Using the option element to define a command
         6. 4.11.3.6 Using the accesskey attribute on a legend element to define a command
         7. 4.11.3.7 Using the accesskey attribute to define a command on other elements
      4. 4.11.4 dialog要素
      5. 4.11.5 Dialog light dismiss

4.11 対話的な要素

4.11.1 details要素

カテゴリー：

フローコンテンツ。

インタラクティブコンテンツ。

パルパブルコンテンツ。

この要素を使用できるコンテキスト：

フローコンテンツが期待される場所。

コンテンツモデル：

1つのsummary要素に続くフローコンテンツ。

text/htmlにおけるタグ省略：

どちらのタグも省略不可。

コンテンツ属性：

グローバル属性

name — 相互に排他的なdetails要素のグループの名前

open — detailsが可視かどうか

アクセシビリティの考慮：

著者向け。

実装者向け。

DOMインターフェイス：

[Exposed=Window]
interface HTMLDetailsElement : HTMLElement {
  [HTMLConstructor] constructor();

  [CEReactions] attribute DOMString name;
  [CEReactions] attribute boolean open;
};

details要素は、ユーザーが追加情報やコントロールを得ることができるディスクロージャーウィジェットを表す。

すべてのHTML要素と同様に、別のタイプのコントロールを表現しようとするときにdetails要素を使用することは適合しない。例えば、タブウィジェットとメニューウィジェットはディスクロージャーウィジェットではないため、details要素を乱用してこれらのパターンを実装するのは誤りである。

details要素は、脚注には適さない。脚注をマークアップする方法の詳細については、脚注のセクションを参照のこと。

要素の子である最初のsummary要素がもしあれば、detailsの要約または凡例を表す。If there is no child summary element, the user agent should provide its own legend (e.g. "Details").

要素のコンテンツの残り部分は、追加情報やコントロールを表す。

nameコンテンツ属性は、要素がメンバーである関連する details要素のグループの名前を与える。このグループの1つのメンバーを開くと、グループの他のメンバーは閉じる。この属性が指定される場合、その値は空文字列であってはならない。

この機能を使用する前に、著者は、関連するdetails要素を排他的なアコーディオンにグループ化することが、ユーザーにとって有用であるか有害であるかを考慮すべきである。排他的なアコーディオンを使用すると、コンテンツのセットが占有できるスペースの最大量を減らすことができるが、必要なものを見つけるために多くのアイテムを開かなければならないユーザー、または同時に複数のアイテムのコンテンツを見たいユーザーをイライラさせることもある。

文書には、open属性が存在する同じdetails name group内に複数のdetails要素を含めてはならない。著者は、open属性をもつ複数のdetails要素をdetails name groupに持たせるような方法で、スクリプトを使用して details要素を文書に追加してはならない。

共通のname属性によって作成される要素のグループは排他的である。つまり、多くとも一度に開くことができるdetails要素は1つのだけである。この排他性はユーザーエージェントによって強制されるが、その結果、マークアップ内のopen属性が即座に変更される。著者に対するこの要件は、そのような誤解を招くようなマークアップを禁止している。

文書には、同じdetails name group内の別のdetails要素の子孫であるdetails要素を含めてはならない。

nameを使用して、複数の関連するdetails要素をグループ化する文書では、それらの関連する要素を包含要素（section要素、article要素など）にまとめるべきである。グループを見出しで導入することに意味がある場合、著者はその見出しを見出し要素内の包含要素の先頭に配置すべきである。

関連する要素を視覚的およびプログラム的にグループ化することは、アクセシブルなユーザーエクスペリエンスにとって重要である。これは、ユーザーがそのような要素間の関係を理解するのに役立つ。関連する要素がグループ化されるのではなく、ウェブページの異なるセクションにある場合、要素間の関係が発見しにくくなったり、理解しにくくなったりすることがある。

openコンテンツ属性は、真偽属性である。存在する場合、この属性は要約と追加情報の両方がユーザーに表示されることを示す。属性が存在しない場合、要約のみが表示されるようになる。

When the element is created, if the attribute is absent, the additional information should be hidden; if the attribute is present, that information should be shown. Subsequently, if the attribute is removed, then the information should be hidden; if the attribute is added, the information should be shown.

The user agent should allow the user to request that the additional information be shown or hidden. To honor a request for the details to be shown, the user agent must set the open attribute on the element to the empty string. To honor a request for the information to be hidden, the user agent must remove the open attribute from the element.

This ability to request that additional information be shown or hidden may simply be the activation behavior of the appropriate summary element, in the case such an element exists. However, if no such element exists, user agents can still provide this ability through some other user interface affordance.

The details name group that contains a details element a also contains all the other details elements b that fulfill all of the following conditions:

• aとbの両方は、同じツリーに属する。
• They both have a name attribute, their name attributes are not the empty string, and the value of a's name attribute equals the value of b's name attribute.

Every details element has a details toggle task tracker, which is a toggle task tracker or null, initially null.

The following attribute change steps, given element, localName, oldValue, value, and namespace, are used for all details elements:

1. If namespace is not null, then return.

2. If localName is name, then ensure details exclusivity by closing the given element if needed given element.

3. If localName is open, then:

   1. If one of oldValue or value is null and the other is not null, run the following steps, which are known as the details notification task steps, for this details element:

      When the open attribute is toggled several times in succession, the resulting tasks essentially get coalesced so that only one event is fired.

      1. If oldValue is null, queue a details toggle event task given the details element, "closed", and "open".

      2. Otherwise, queue a details toggle event task given the details element, "open", and "closed".

   2. If oldValue is null and value is not null, then ensure details exclusivity by closing other elements if needed given element.

The details HTML element insertion steps, given insertedNode, are:

1. Ensure details exclusivity by closing the given element if needed given insertedNode.

To be clear, these attribute change and insertion steps also run when an attribute or element is inserted via the parser.

To queue a details toggle event task given a details element element, a string oldState, and a string newState:

1. If element's details toggle task tracker is not null, then:

   1. Set oldState to element's details toggle task tracker's old state.

   2. Remove element's details toggle task tracker's task from its task queue.

   3. Set element's details toggle task tracker to null.

2. Queue an element task given the DOM manipulation task source and element to run the following steps:

   1. Fire an event named toggle at element, using ToggleEvent, with the oldState attribute initialized to oldState and the newState attribute initialized to newState.

   2. Set element's details toggle task tracker to null.

3. Set element's details toggle task tracker to a struct with task set to the just-queued task and old state set to oldState.

To ensure details exclusivity by closing other elements if needed given a details element element:

1. Assert: element has an open attribute.

2. If element does not have a name attribute, or its name attribute is the empty string, then return.

3. Let groupMembers be a list of elements, containing all elements in element's details name group except for element, in tree order.

4. For each element otherElement of groupMembers:

   1. If the open attribute is set on otherElement, then:

      1. Assert: otherElement is the only element in groupMembers that has the open attribute set.

      2. Remove the open attribute on otherElement.

      3. Break.

To ensure details exclusivity by closing the given element if needed given a details element element:

1. If element does not have an open attribute, then return.

2. If element does not have a name attribute, or its name attribute is the empty string, then return.

3. Let groupMembers be a list of elements, containing all elements in element's details name group except for element, in tree order.

4. For each element otherElement of groupMembers:

   1. If the open attribute is set on otherElement, then:

      1. Remove the open attribute on element.

      2. Break.

The name and open IDL attributes must reflect the respective content attributes of the same name.

The ancestor details revealing algorithm is to run the following steps on currentNode:

1. While currentNode has a parent node within the flat tree:

   1. If currentNode is slotted into the second slot of a details element:

      1. Set currentNode to the details element which currentNode is slotted into.

      2. If the open attribute is not set on currentNode, then set the open attribute on currentNode to the empty string.

   2. Otherwise, set currentNode to the parent node of currentNode within the flat tree.

<section class="progress window">
 <h1>Copying "Really Achieving Your Childhood Dreams"</h1>
 <details>
  <summary>Copying... <progress max="375505392" value="97543282"></progress> 25%</summary>
  <dl>
   <dt>Transfer rate:</dt> <dd>452KB/s</dd>
   <dt>Local filename:</dt> <dd>/home/rpausch/raycd.m4v</dd>
   <dt>Remote filename:</dt> <dd>/var/www/lectures/raycd.m4v</dd>
   <dt>Duration:</dt> <dd>01:16:27</dd>
   <dt>Color profile:</dt> <dd>SD (6-1-6)</dd>
   <dt>Dimensions:</dt> <dd>320×240</dd>
  </dl>
 </details>
</section>

<details>
 <summary><label for=fn>Name & Extension:</label></summary>
 <p><input type=text id=fn name=fn value="Pillar Magazine.pdf">
 <p><label><input type=checkbox name=ext checked> Hide extension</label>
</details>

<section class="characteristics">
 <details name="frame-characteristics">
  <summary>Material</summary>
  The picture frame is made of solid oak wood.
 </details>
 <details name="frame-characteristics">
  <summary>Size</summary>
  The picture frame fits a photo 40cm tall and 30cm wide.
  The frame is 45cm tall, 35cm wide, and 2cm thick.
 </details>
 <details name="frame-characteristics">
  <summary>Color</summary>
  The picture frame is available in its natural wood
  color, or with black stain.
 </details>
</section>

<section class="characteristics">
 <details name="frame-characteristics" id="d1" open>...</details>
 <details name="frame-characteristics" id="d2">...</details>
 <details name="frame-characteristics" id="d3">...</details>
</section>

document.getElementById("d2").setAttribute("open", "");

<section class="characteristics">
 <details name="frame-characteristics" id="d1">...</details>
 <details name="frame-characteristics" id="d2" open>...</details>
 <details name="frame-characteristics" id="d3">...</details>
</section>

<style>
 details > summary { transition: color 1s; color: black; }
 details[open] > summary { color: red; }
</style>
<details>
 <summary>Automated Status: Operational</summary>
 <p>Velocity: 12m/s</p>
 <p>Direction: North</p>
</details>

4.11.2 summary要素

カテゴリー：

なし。

この要素を使用できるコンテキスト：

details要素の最初の子として。

コンテンツモデル：

フレージングコンテンツ、オプションでヘディングコンテンツと混合される。

text/htmlにおけるタグ省略：

どちらのタグも省略不可。

コンテンツ属性：

グローバル属性

アクセシビリティの考慮：

著者向け。

実装者向け。

DOMインターフェイス：

HTMLElementを使用する。

summary要素は、もしあれば、summary要素の親details要素に属する残りの内容のキャプションまたは凡例を表す。

A summary element is a summary for its parent details if the following algorithm returns true:

1. If this summary element has no parent, then return false.

2. Let parent be this summary element's parent.

3. If parent is not a details element, then return false.

4. If parent's first summary element child is not this summary element, then return false.

5. Return true.

The activation behavior of summary elements is to run the following steps:

1. If this summary element is not the summary for its parent details, then return.

2. Let parent be this summary element's parent.

3. If the open attribute is present on parent, then remove it. Otherwise, set parent's open attribute to the empty string.

   This will then run the details notification task steps.

4.11.3 コマンド

4.11.3.1 ファセット

コマンドは、メニュー項目、ボタン、リンクの背後に抽象化したものである。一度コマンドが定義されると、インターフェイスの他の部分は、Disabled状態のようなファセットを共有するために単一の機能へ多くのアクセスポイントを許可し、同じコマンドを参照できる。

コマンドは、次のファセットを持つように定義される：

ラベル

ユーザーから見たコマンドの名前。

アクセスキー

コマンドを切り替えるユーザーエージェントによって選択されたキーの組み合わせ。コマンドはアクセスキーを持たないかもしれない。

Hidden状態

コマンドが非表示にされたかどうか（基本的に、メニューに表示するかどうか）。

Disabled状態

コマンドが関連するおよび切り替え可能かどうか。

アクション

コマンドを切り替える実際の効果がもつもの。これは、スクリプト化されたイベントハンドラー、どのようにナビゲートするためのURL、またはフォーム送信であるかもしれない。

ユーザーエージェントは、次の条件に一致するコマンドを公開してもよい：

• Hidden Stateのファセットはfalseである（可視）。

• 要素は、nullでないブラウジングコンテキストをもつ文書内である。

• 要素もその祖先のいずれも指定されたhidden属性を持たない。

ユーザーエージェントは、ユーザーにこれらのキーを通知するための方法として、アクセスキーを持つコマンドのために特にこれを行うことが推奨される。

たとえば、そのようなコマンドは、ユーザーエージェントのメニューバーにリストされるかもしれない。

4.11.3.2 Using the a element to define a command

An a element with an href attribute defines a command.

The Label of the command is the element's descendant text content.

The Access Key of the command is the element's assigned access key, if any.

The Hidden State of the command is true (hidden) if the element has a hidden attribute, and false otherwise.

The Disabled State facet of the command is true if the element or one of its ancestors is inert, and false otherwise.

The Action of the command is to fire a click event at the element.

4.11.3.3 Using the button element to define a command

A button element always defines a command.

The Label, Access Key, Hidden State, and Action facets of the command are determined as for a elements (see the previous section).

The Disabled State of the command is true if the element or one of its ancestors is inert, or if the element's disabled state is set, and false otherwise.

4.11.3.4 Using the input element to define a command

An input element whose type attribute is in one of the Submit Button, Reset Button, Image Button, Button, Radio Button, or Checkbox states defines a command.

The Label of the command is determined as follows:

• If the type attribute is in one of the Submit Button, Reset Button, Image Button, or Button states, then the Label is the string given by the value attribute, if any, and a UA-dependent, locale-dependent value that the UA uses to label the button itself if the attribute is absent.

• Otherwise, if the element is a labeled control, then the Label is the descendant text content of the first label element in tree order whose labeled control is the element in question. (In JavaScript terms, this is given by element.labels[0].textContent.)

• Otherwise, if the value attribute is present, then the Label is the value of that attribute.

• Otherwise, the Label is the empty string.

The Access Key of the command is the element's assigned access key, if any.

The Hidden State of the command is true (hidden) if the element has a hidden attribute, and false otherwise.

The Disabled State of the command is true if the element or one of its ancestors is inert, or if the element's disabled state is set, and false otherwise.

The Action of the command is to fire a click event at the element.

4.11.3.5 Using the option element to define a command

An option element with an ancestor select element and either no value attribute or a value attribute that is not the empty string defines a command.

The Label of the command is the value of the option element's label attribute, if there is one, or else the option element's descendant text content, with ASCII whitespace stripped and collapsed.

The Access Key of the command is the element's assigned access key, if any.

The Hidden State of the command is true (hidden) if the element has a hidden attribute, and false otherwise.

The Disabled State of the command is true if the element is disabled, or if its nearest ancestor select element is disabled, or if it or one of its ancestors is inert, and false otherwise.

If the option's nearest ancestor select element has a multiple attribute, the Action of the command is to toggle the option element. Otherwise, the Action is to pick the option element.

4.11.3.6 Using the accesskey attribute on a legend element to define a command

A legend element defines a command if all of the following are true:

• It has an assigned access key.

• It is a child of a fieldset element.

• Its parent has a descendant that defines a command that is neither a label element nor a legend element. This element, if it exists, is the legend element's accesskey delegatee.

The Label of the command is the element's descendant text content.

The Access Key of the command is the element's assigned access key.

The Hidden State, Disabled State, and Action facets of the command are the same as the respective facets of the legend element's accesskey delegatee.

<fieldset>
 <legend accesskey=p>
  <label>I want <input name=pizza type=number step=1 value=1 min=0>
   pizza(s) with these toppings</label>
 </legend>
 <label><input name=pizza-cheese type=checkbox checked> Cheese</label>
 <label><input name=pizza-ham type=checkbox checked> Ham</label>
 <label><input name=pizza-pineapple type=checkbox> Pineapple</label>
</fieldset>

4.11.3.7 Using the accesskey attribute to define a command on other elements

An element that has an assigned access key defines a command.

If one of the earlier sections that define elements that define commands define that this element defines a command, then that section applies to this element, and this section does not. Otherwise, this section applies to that element.

The Label of the command depends on the element. If the element is a labeled control, the descendant text content of the first label element in tree order whose labeled control is the element in question is the Label (in JavaScript terms, this is given by element.labels[0].textContent). Otherwise, the Label is the element's descendant text content.

The Access Key of the command is the element's assigned access key.

The Hidden State of the command is true (hidden) if the element has a hidden attribute, and false otherwise.

The Disabled State of the command is true if the element or one of its ancestors is inert, and false otherwise.

The Action of the command is to run the following steps:

1. Run the focusing steps for the element.
2. Fire a click event at the element.

4.11.4 dialog要素

カテゴリー：

フローコンテンツ。

この要素を使用できるコンテキスト：

フローコンテンツが期待される場所。

コンテンツモデル：

フローコンテンツ。

text/htmlにおけるタグ省略：

どちらのタグも省略不可。

コンテンツ属性：

グローバル属性

closedby — ダイアログを閉じるユーザーアクション

open — ダイアログボックスが見えるかどうか

アクセシビリティの考慮：

著者向け。

実装者向け。

DOMインターフェイス：

[Exposed=Window]
interface HTMLDialogElement : HTMLElement {
  [HTMLConstructor] constructor();

  [CEReactions] attribute boolean open;
  attribute DOMString returnValue;
  [CEReactions] attribute DOMString closedBy;
  [CEReactions] undefined show();
  [CEReactions] undefined showModal();
  [CEReactions] undefined close(optional DOMString returnValue);
  [CEReactions] undefined requestClose(optional DOMString returnValue);
};

dialog要素は、小さいウィンドウ（"ダイアログボックス"）の形式で、ユーザーはこのウィンドウを操作してタスクを実行したり、情報を収集したりする、アプリケーションの一時的な部分を表す。ユーザーが終了すると、ダイアログはアプリケーションによって自動的に閉じる、またはユーザーによって手動で閉じることができる。

すべてのタイプのアプリケーションでおなじみのパターンである、特にモーダルダイアログの場合、著者は、ウェブアプリケーション内のダイアログが、非ウェブアプリケーションのユーザーにも馴染みのある方法で動作するように保証すべきである。

すべてのHTML要素と同様に、別のタイプのコントロールを表現しようとするときにdialog要素を使用することは適合しない。たとえば、コンテキストメニュー、ツールチップ、ポップアップリストボックスは、ダイアログボックスではないため、これらのパターンを実装するためにdialog要素を乱用することは正しくない。

ユーザー向けダイアログの動作で重要な部分は、初期のフォーカスの配置である。ダイアログフォーカスステップは、ダイアログが表示されたときに初期のフォーカスの適切な候補を選択しようするが、特定のダイアログに対するユーザーの期待に沿う正確な選択を慎重に検討する著者の代わりにはならないかもしれない。そのため、著者は、ダイアログが開いた後にユーザーがすぐに対話することが期待されるダイアログの子孫要素に対して、autofocus属性を使用すべきである。そのような要素がない場合、著者はdialog要素自体にautofocus属性を使用すべきである。

<dialog>
  <label>Product Number <input type="text" readonly></label>
  <label>Product Name <input type="text" autofocus></label>
</dialog>

ユーザー動作のもう1つの重要な側面は、ダイアログがスクロール可能かどうかということである。場合によっては、オーバーフロー（つまりスクロール可能性）は、例えば、ユーザーの高いテキストズーム設定によって引き起こされる場合、回避することができない。しかし一般に、スクロール可能なダイアログはユーザーには期待されない。大きなテキストノードをダイアログ要素に直接追加すると、ダイアログ要素自体がオーバーフローする可能性があるため、特に問題が多い。著者はそれらを避けるのが最善である。

<dialog style="height: 80vh;">
  <div style="overflow: auto; height: 60vh;" autofocus>
    <p>By placing an order via this Web site on the first day of the fourth month of the year
    2010 Anno Domini, you agree to grant Us a non-transferable option to claim, for now and for
    ever more, your immortal soul.</p>
    <p>Should We wish to exercise this option, you agree to surrender your immortal soul,
    and any claim you may have on it, within 5 (five) working days of receiving written
    notification from  this site or one of its duly authorized minions.</p>
    <!-- ... etc., with many more <p> elements ... -->
  </div>
  <form method="dialog">
    <button type="submit" value="agree">Agree</button>
    <button type="submit" value="disagree">Disagree</button>
  </form>
</dialog>

<dialog>
 <h1>Add to Wallet</h1>
 <p><strong><label for=amt>How many gold coins do you want to add to your wallet?</label></strong></p>
 <p><input id=amt name=amt type=number min=0 step=0.01 value=100></p>
 <p><small>You add coins at your own risk.</small></p>
 <p><label><input name=round type=checkbox> Only add perfectly round coins</label></p>
 <p><input type=button onclick="submit()" value="Add Coins"></p>
</dialog>

open属性は、真偽属性である。指定される場合、dialog要素はアクティブであり、ユーザーが操作できることを示す。

closedbyコンテンツ属性は、次のキーワードと状態をもつ列挙属性である：

closedby属性の不正値のデフォルトと欠損値のデフォルトの両方は、Auto状態である。

Auto状態は、dialogがそのshowModal()メソッドを使用して表示された場合、閉じ要求状態として動作し、そうでなければNone状態として動作する。

open属性が指定されないdialog要素は、ユーザーに表示されるべきでない。この要件は、スタイルレイヤーを通して間接的に実装されてもよい。たとえば、推奨されるデフォルトのレンダリングをサポートするユーザーエージェントは、Renderingセクションで説明されるCSSルールを使用してこの要件を実装する。

tabindex属性は、dialog要素で指定されてはならない。

dialog.show()

✔MDN

HTMLDialogElement/show

Support in all current engines.

Firefox98+Safari15.4+Chrome37+

---

Opera?Edge79+

---

Edge (Legacy)?Internet ExplorerNo

---

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

dialog要素を表示する。

dialog.showModal()

✔MDN

HTMLDialogElement/showModal

Support in all current engines.

Firefox98+Safari15.4+Chrome37+

---

Opera?Edge79+

---

Edge (Legacy)?Internet ExplorerNo

---

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

dialog要素を表示し、一番上のモーダルダイアログにする。

この方法は、autofocus属性を履行する。

dialog.close([ result ])

✔MDN

HTMLDialogElement/close

Support in all current engines.

Firefox98+Safari15.4+Chrome37+

---

Opera?Edge79+

---

Edge (Legacy)?Internet ExplorerNo

---

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

dialog要素を閉じる。

引数が与えられた場合、戻り値を提供する。

dialog.requestClose([ result ])

最初にcancelイベントを発火し、そのイベントがpreventDefault()でキャンセルされない場合、close()メソッドと同じ方法でdialogを閉じる（closeイベントの起動を含む）。これにより、dialogをターゲットとして閉じ要求が送信されたかのように動作する。

これは、キャンセルおよびクローズロジックをcancelおよびcloseイベントハンドラーに統合するために使用できるヘルパーユーティリティであり、非close requestのすべてのクローズアフォーダンスでこのメソッドを呼び出すことができる。

このメソッドはclosedby属性を無視する。つまり、closedbyが"none"に設定されていても、同じ動作が適用される。

引数が与えられた場合、戻り値を提供する。

dialog.returnValue [ = result ]

✔MDN

HTMLDialogElement/returnValue

Support in all current engines.

Firefox98+Safari15.4+Chrome37+

---

Opera?Edge79+

---

Edge (Legacy)?Internet ExplorerNo

---

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

dialogの戻り値を返す。

戻り値を更新する設定が可能である。

The show() method steps are:

1. If this has an open attribute and is modal of this is false, then return.

2. If this has an open attribute, then throw an "InvalidStateError" DOMException.

3. If the result of firing an event named beforetoggle, using ToggleEvent, with the cancelable attribute initialized to true, the oldState attribute initialized to "closed", and the newState attribute initialized to "open" at this is false, then return.

4. If this has an open attribute, then return.

5. Queue a dialog toggle event task given this, "closed", and "open".

6. Add an open attribute to this, whose value is the empty string.

7. Assert: this's node document's open dialogs list does not contain this.

8. Add this to this's node document's open dialogs list.

9. Set the dialog close watcher with this.

10. Set this's previously focused element to the focused element.

11. Let document be this's node document.

12. Let hideUntil be the result of running topmost popover ancestor given this, document's showing hint popover list, null, and false.

13. If hideUntil is null, then set hideUntil to the result of running topmost popover ancestor given this, document's showing auto popover list, null, and false.

14. If hideUntil is null, then set hideUntil to document.

15. Run hide all popovers until given hideUntil, false, and true.

16. Run the dialog focusing steps given this.

The showModal() method steps are to show a modal dialog given this.

The close(returnValue) method steps are:

1. If returnValue is not given, then set it to null.

2. Close the dialog this with returnValue.

The requestClose(returnValue) method steps are:

1. If this does not have an open attribute, then return.

2. Assert: this's close watcher is not null.

3. Set dialog's enable close watcher for requestClose() to true.

4. If returnValue is not given, then set it to null.

5. Set this's request close return value to returnValue.

6. Request to close dialog's close watcher with false.

7. Set dialog's enable close watcher for requestClose() to false.

The returnValue IDL attribute, on getting, must return the last value to which it was set. On setting, it must be set to the new value. When the element is created, it must be set to the empty string.

The closedBy getter steps are to return the keyword corresponding to the computed closed-by state given this.

The closedBy setter steps are to set the closedby content attribute to the given value.

open IDL属性は、openコンテンツ属性を反映しなければならない。

Each Document has a dialog pointerdown target, which is an HTML dialog element or null, initially null.

Each HTML element has a previously focused element which is null or an element, and it is initially null. When showModal() and show() are called, this element is set to the currently focused element before running the dialog focusing steps. Elements with the popover attribute set this element to the currently focused element during the show popover algorithm.

Each dialog element has a dialog toggle task tracker, which is a toggle task tracker or null, initially null.

Each dialog element has a close watcher, which is a close watcher or null, initially null.

Each dialog element has a request close return value, which is a string, initially null.

Each dialog element has an enable close watcher for requestClose() boolean, initially false.

Each dialog element has an is modal boolean, initially false.

The dialog HTML element removing steps, given removedNode and oldParent, are:

1. If removedNode's close watcher is not null, then:

   1. Destroy removedNode's close watcher.

   2. Set removedNode's close watcher to null.

2. If removedNode's node document's top layer contains removedNode, then remove an element from the top layer immediately given removedNode.

3. Set is modal of removedNode to false.

4. Remove removedNode from removedNode's node document's open dialogs list.

To show a modal dialog given a dialog element subject:

1. If subject has an open attribute and is modal of subject is true, then return.

2. If subject has an open attribute, then throw an "InvalidStateError" DOMException.

3. If subject's node document is not fully active, then throw an "InvalidStateError" DOMException.

4. If subject is not connected, then throw an "InvalidStateError" DOMException.

5. If subject is in the popover showing state, then throw an "InvalidStateError" DOMException.

6. If the result of firing an event named beforetoggle, using ToggleEvent, with the cancelable attribute initialized to true, the oldState attribute initialized to "closed", and the newState attribute initialized to "open" at subject is false, then return.

7. If subject has an open attribute, then return.

8. If subject is not connected, then return.

9. If subject is in the popover showing state, then return.

10. Queue a dialog toggle event task given subject, "closed", and "open".

11. Add an open attribute to subject, whose value is the empty string.

12. Set is modal of subject to true.

13. Assert: subject's node document's open dialogs list does not contain subject.

14. Add subject to subject's node document's open dialogs list.

15. Let subject's node document be blocked by the modal dialog subject.

    This will cause the focused area of the document to become inert (unless that currently focused area is a shadow-including descendant of subject). In such cases, the focused area of the document will soon be reset to the viewport. In a couple steps we will attempt to find a better candidate to focus.

16. If subject's node document's top layer does not already contain subject, then add an element to the top layer given subject.

17. Set the dialog close watcher with subject.

18. Set subject's previously focused element to the focused element.

19. Let document be subject's node document.

20. Let hideUntil be the result of running topmost popover ancestor given subject, document's showing hint popover list, null, and false.

21. If hideUntil is null, then set hideUntil to the result of running topmost popover ancestor given subject, document's showing auto popover list, null, and false.

22. If hideUntil is null, then set hideUntil to document.

23. Run hide all popovers until given hideUntil, false, and true.

24. Run the dialog focusing steps given subject.

To set the dialog close watcher, given a dialog element dialog:

1. Set dialog's close watcher to the result of establishing a close watcher given dialog's relevant global object, with:

   • cancelAction given canPreventClose being to return the result of firing an event named cancel at dialog, with the cancelable attribute initialized to canPreventClose.

   • closeAction being to close the dialog given dialog and dialog's request close return value.

   • getEnabledState being to return true if dialog's enable close watcher for requestClose() is true or dialog's computed closed-by state is not None; otherwise false.

The is valid invoker command steps for dialog elements, given a command attribute command, are:

1. If command is in the Close state or in the Show Modal state, then return true.

2. falseを返す。

The invoker command steps for dialog elements, given an element element, an element invoker, and a command attribute command, are:

1. If element is in the popover showing state, then return.

2. If command is in the Close state and element has an open attribute:

   1. Let value be invoker's value.

   2. Close the dialog element with value.

3. If command is the Show Modal state and element does not have an open attribute, then show a modal dialog given element.

<button type=button
        commandfor="the-dialog"
        command="show-modal">
 Delete
</button>
<dialog id="the-dialog">
 <form action="/delete" method="POST">
  <button type="submit">
   Delete
  </button>
  <button commandfor="the-dialog"
          command="close">
   Cancel
  </button>
 </form>
</dialog>
    

When a dialog element subject is to be closed, with null or a string result, run these steps:

1. If subject does not have an open attribute, then return.

2. Fire an event named beforetoggle, using ToggleEvent, with the oldState attribute initialized to "open" and the newState attribute initialized to "closed" at subject.

3. If subject does not have an open attribute, then return.

4. Queue a dialog toggle event task given subject, "open", and "closed".

5. Remove subject's open attribute.

6. If is modal of subject is true, then request an element to be removed from the top layer given subject.

7. Let wasModal be the value of subject's is modal flag.

8. Set is modal of subject to false.

9. Remove subject from subject's node document's open dialogs list.

10. If result is not null, then set the returnValue attribute to result.

11. Set the request close return value to null.

12. If subject's previously focused element is not null, then:

    1. Let element be subject's previously focused element.

    2. Set subject's previously focused element to null.

    3. If subject's node document's focused area of the document's DOM anchor is a shadow-including inclusive descendant of subject, or wasModal is true, then run the focusing steps for element; the viewport should not be scrolled by doing this step.

13. Queue an element task on the user interaction task source given the subject element to fire an event named close at subject.

14. If subject's close watcher is not null, then:

    1. Destroy subject's close watcher.

    2. Set subject's close watcher to null.

To queue a dialog toggle event task given a dialog element element, a string oldState, and a string newState:

1. If element's dialog toggle task tracker is not null, then:

   1. Set oldState to element's dialog toggle task tracker's old state.

   2. Remove element's dialog toggle task tracker's task from its task queue.

   3. Set element's dialog toggle task tracker to null.

2. Queue an element task given the DOM manipulation task source and element to run the following steps:

   1. Fire an event named toggle at element, using ToggleEvent, with the oldState attribute initialized to oldState and the newState attribute initialized to newState.

   2. Set element's dialog toggle task tracker to null.

3. Set element's dialog toggle task tracker to a struct with task set to the just-queued task and old state set to oldState.

To retrieve a dialog's computed closed-by state, given a dialog dialog:

1. If the state of dialog's closedby attribute is Auto:

   1. If dialog's is modal is true, then return Close Request.

   2. Return None.

2. Return the state of dialog's closedby attribute.

The dialog focusing steps, given a dialog element subject, are as follows:

1. If the allow focus steps given subject's node document return false, then return.

2. Let control be null.

3. If subject has the autofocus attribute, then set control to subject.

4. If control is null, then set control to the focus delegate of subject.

5. If control is null, then set control to subject.

6. Run the focusing steps for control.

   If control is not focusable, this will do nothing. This would only happen if subject had no focus delegate, and the user agent decided that dialog elements were not generally focusable. In that case, any earlier modifications to the focused area of the document will apply.

7. Let topDocument be control's node navigable's top-level traversable's active document.

8. If control's node document's origin is not the same as the origin of topDocument, then return.

9. Empty topDocument's autofocus candidates.

10. Set topDocument's autofocus processed flag to true.

4.11.5 Dialog light dismiss

"Light dismiss" means that clicking outside of a dialog element whose closedby attribute is in the Any state will close the dialog element. This is in addition to how such dialogs respond to close requests.

To light dismiss open dialogs, given a PointerEvent event:

1. Assert: event's isTrusted attribute is true.

2. Let document be event's target's node document.

3. If document's open dialogs list is empty, then return.

4. Let ancestor be the result of running nearest clicked dialog given event.

5. If event's type is "pointerdown", then set document's dialog pointerdown target to ancestor.

6. If event's type is "pointerup", then:

   1. Let sameTarget be true if ancestor is document's dialog pointerdown target.

   2. Set document's dialog pointerdown target to null.

   3. If sameTarget is false, then return.

   4. Let topmostDialog be the last element of document's open dialogs list.

   5. If ancestor is topmostDialog, then return.

   6. If topmostDialog's computed closed-by state is not Any, then return.

   7. Assert: topmostDialog's close watcher is not null.

   8. Request to close topmostDialog's close watcher with false.

To run light dismiss activities, given a PointerEvent event:

1. Run light dismiss open popovers with event.

2. Run light dismiss open dialogs with event.

Run light dismiss activities will be called by the Pointer Events spec when the user clicks or touches anywhere on the page.

To find the nearest clicked dialog, given a PointerEvent event:

1. Let target be event's target.

2. If target is a dialog element, target has an open attribute, target's is modal is true, and event's clientX and clientY are outside the bounds of target, then return null.

   The check for clientX and clientY is because a pointer event that hits the ::backdrop pseudo element of a dialog will result in event having a target of the dialog element itself.

3. Let currentNode be target.

4. While currentNode is not null:

   1. If currentNode is a dialog element and currentNode has an open attribute, then return currentNode.

   2. Set currentNode to currentNode's parent in the flat tree.

5. Return null.