From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/html/element%2Fdialog.html | 225 +++++++++++++++++++++++++++++++++++++ 1 file changed, 225 insertions(+) create mode 100644 devdocs/html/element%2Fdialog.html (limited to 'devdocs/html/element%2Fdialog.html') diff --git a/devdocs/html/element%2Fdialog.html b/devdocs/html/element%2Fdialog.html new file mode 100644 index 00000000..9cdc464f --- /dev/null +++ b/devdocs/html/element%2Fdialog.html @@ -0,0 +1,225 @@ +

<dialog>: The Dialog element

+

The <dialog> HTML element represents a modal or non-modal dialog box or other interactive component, such as a dismissible alert, inspector, or subwindow.

The HTML <dialog> element is used to create both modal and non-modal dialog boxes. Modal dialog boxes interrupt interaction with the rest of the page being inert, while non-modal dialog boxes allow interaction with the rest of the page.

JavaScript should be used to display the <dialog> element. Use the .showModal() method to display a modal dialog and the .show() method to display a non-modal dialog. The dialog box can be closed using the .close() method or using the dialog method when submitting a <form> that is nested within the <dialog> element. Modal dialogs can also be closed by pressing the Esc key.

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+

Attributes

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This element includes the global attributes.

Warning: The tabindex attribute must not be used on the <dialog> element.

open

Indicates that the dialog box is active and is available for interaction. If the open attribute is not set, the dialog box will not be visible to the user. It is recommended to use the .show() or .showModal() method to render dialogs, rather than the open attribute. If a <dialog> is opened using the open attribute, it is non-modal.

Note: While you can toggle between the open and closed states of non-modal dialog boxes by toggling the presence of the open attribute, this approach is not recommended.

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Usage notes

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Examples

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Caveats of creating a dialog using only HTML

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This example demonstrates the create a non-modal dialog by using only HTML. Because of the boolean open attribute in the <dialog> element, the dialog appears open when the page loads. The dialog can be closed by clicking the "OK" button because the method attribute in the <form> element is set to "dialog". In this case, no JavaScript is needed to close the form.

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html

+
<dialog open>
+  <p>Greetings, one and all!</p>
+  <form method="dialog">
+    <button>OK</button>
+  </form>
+</dialog>
+
+

Result

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+ + +

This dialog is initially open because of the presence of the open attribute. Dialogs that are displayed using the open attribute are non-modal. You may notice that after clicking "OK", the dialog gets dismissed leaving the Result frame empty. When the dialog is dismissed, there is no method provided to reopen it. For this reason, the preferred method to display non-modal dialogs is by using the HTMLDialogElement.show() method. It is possible to toggle the display of the dialog by adding or removing the boolean open attribute, but it is not the recommended practice.

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Creating a modal dialog

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This example demonstrates a modal dialog with a gradient backdrop. The .showModal() method opens the modal dialog when the "Show the dialog" button is activated. The dialog can be closed by pressing the Esc key or via the close() method when the "Close" button within the dialog is activated.

When a dialog opens, the browser, by default, gives focus to the first element that can be focused within the dialog. In this example, the autofocus attribute is applied to the "Close" button, giving it focus when the dialog opens, as this is the element we expect the user will interact with immediately after the dialog opens.

HTML

+

html

+
<dialog>
+  <button autofocus>Close</button>
+  <p>This modal dialog has a groovy backdrop!</p>
+</dialog>
+<button>Show the dialog</button>
+
+

CSS

We can style the backdrop of the dialog by using the ::backdrop pseudo-element.

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css

+
::backdrop {
+  background-image: linear-gradient(
+    45deg,
+    magenta,
+    rebeccapurple,
+    dodgerblue,
+    green
+  );
+  opacity: 0.75;
+}
+
+

JavaScript

The dialog is opened modally using the .showModal() method and closed using the .close() method.

+

js

+
const dialog = document.querySelector("dialog");
+const showButton = document.querySelector("dialog + button");
+const closeButton = document.querySelector("dialog button");
+
+// "Show the dialog" button opens the dialog modally
+showButton.addEventListener("click", () => {
+  dialog.showModal();
+});
+
+// "Close" button closes the dialog
+closeButton.addEventListener("click", () => {
+  dialog.close();
+});
+
+

Result

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When the modal dialog is displayed, it appears above any other dialogs that might be present. Everything outside the modal dialog is inert and interactions outside the dialog are blocked. Notice that when the dialog is open, with the exception of the dialog itself, interaction with the document is not possible; the "Show the dialog" button is mostly obfuscated by the almost opaque backdrop of the dialog and is inert.

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Handling the return value from the dialog

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This example demonstrates the returnValue of the <dialog> element and how to close a modal dialog by using a form. By default, the returnValue is the empty string or the value of the button that submits the form within the <dialog> element, if there is one.

This example opens a modal dialog when the "Show the dialog" button is activated. The dialog contains a form with a <select> and two <button> elements, which default to type="submit". An eventlistener updates the value of the "Confirm" button when the select option changes. If the "Confirm" button is activated to close the dialog, the current value of the button is the return value. If the dialog is closed by pressing the "Cancel" button, the returnValue is cancel.

When the dialog is closed, the return value is displayed under the "Show the dialog" button. If the dialog is closed by pressing the Esc key, the returnValue is not updated and the close event doesn't occur so the text in the <output> is not updated.

HTML

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html

+
<!-- A modal dialog containing a form -->
+<dialog id="favDialog">
+  <form>
+    <p>
+      <label>
+        Favorite animal:
+        <select>
+          <option value="default">Choose…</option>
+          <option>Brine shrimp</option>
+          <option>Red panda</option>
+          <option>Spider monkey</option>
+        </select>
+      </label>
+    </p>
+    <div>
+      <button value="cancel" formmethod="dialog">Cancel</button>
+      <button id="confirmBtn" value="default">Confirm</button>
+    </div>
+  </form>
+</dialog>
+<p>
+  <button id="showDialog">Show the dialog</button>
+</p>
+<output></output>
+
+

JavaScript

+

js

+
const showButton = document.getElementById("showDialog");
+const favDialog = document.getElementById("favDialog");
+const outputBox = document.querySelector("output");
+const selectEl = favDialog.querySelector("select");
+const confirmBtn = favDialog.querySelector("#confirmBtn");
+
+// "Show the dialog" button opens the <dialog> modally
+showButton.addEventListener("click", () => {
+  favDialog.showModal();
+});
+
+// "Favorite animal" input sets the value of the submit button
+selectEl.addEventListener("change", (e) => {
+  confirmBtn.value = selectEl.value;
+});
+
+// "Cancel" button closes the dialog without submitting because of [formmethod="dialog"], triggering a close event.
+favDialog.addEventListener("close", (e) => {
+  outputBox.value =
+    favDialog.returnValue === "default"
+      ? "No return value."
+      : `ReturnValue: ${favDialog.returnValue}.`; // Have to check for "default" rather than empty string
+});
+
+// Prevent the "confirm" button from the default behavior of submitting the form, and close the dialog with the `close()` method, which triggers the "close" event.
+confirmBtn.addEventListener("click", (event) => {
+  event.preventDefault(); // We don't want to submit this fake form
+  favDialog.close(selectEl.value); // Have to send the select box value here.
+});
+
+
+
+

Result

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+ + +

This example demonstrates the following three methods of closing modal dialogs:

The "Cancel" button includes the formmethod="dialog" attribute, which overrides the <form>'s default GET method. When a form's method is dialog, the state of the form is saved but not submitted, and the dialog gets closed.

Without an action, submitting the form via the default GET method causes a page to reload. We use JavaScript to prevent the submission and close the dialog with the event.preventDefault() and HTMLDialogElement.close() methods, respectively.

It is important to provide a closing mechanism within every dialog element. The Esc key does not close non-modal dialogs by default, nor can one assume that a user will even have access to a physical keyboard (e.g., someone using a touch screen device without access to a keyboard).

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Technical summary

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Content categories Flow content, sectioning root
Permitted content Flow content
Tag omission None, both the starting and ending tag are mandatory.
Permitted parents Any element that accepts flow content
Implicit ARIA role dialog
Permitted ARIA roles alertdialog
DOM interface HTMLDialogElement
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Accessibility considerations

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When implementing a dialog, it is important to consider the most appropriate place to set user focus. When using HTMLDialogElement.showModal() to open a <dialog>, focus is set on the first nested focusable element. Explicitly indicating the initial focus placement by using the autofocus attribute will help ensure initial focus is set on the element deemed the best initial focus placement for any particular dialog. When in doubt, as it may not always be known where initial focus could be set within a dialog, particularly for instances where a dialog's content is dynamically rendered when invoked, the <dialog> element itself may provide the best initial focus placement.

Ensure a mechanism is provided to allow users to close the dialog. The most robust way to ensure that all users can close the dialog is to include an explicit button to do so, such as a confirmation, cancellation, or close button.

By default, a dialog invoked by the showModal() method can be dismissed by pressing the Esc key. A non-modal dialog does not dismiss via the Esc key by default, and depending on what the non-modal dialog represents, it may not be desired for this behavior. Keyboard users expect the Esc key to close modal dialogs; ensure that this behavior is implemented and maintained. If multiple modal dialogs are open, pressing the Esc key should close only the last shown dialog. When using <dialog>, this behavior is provided by the browser.

While dialogs can be created using other elements, the native <dialog> element provides usability and accessibility features that must be replicated if you use other elements for a similar purpose. If you're creating a custom dialog implementation, ensure that all expected default behaviors are supported and proper labeling recommendations are followed.

The <dialog> element is exposed by browsers in a manner similar to custom dialogs that use the ARIA role="dialog" attribute. <dialog> elements invoked by the showModal() method implicitly have aria-modal="true", whereas <dialog> elements invoked by the show() method or displayed using the open attribute or by changing the default display of a <dialog> are exposed as [aria-modal="false"]. When implementing modal dialogs, everything other than the <dialog> and its contents should be rendered inert using the inert attribute. When using <dialog> along with the HTMLDialogElement.showModal() method, this behavior is provided by the browser.

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Specifications

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Specification
HTML Standard
# the-dialog-element
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Browser compatibility

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+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariWebView AndroidChrome AndroidFirefox for AndroidOpera AndroidSafari on IOSSamsung Internet
dialog377998No2415.43737982415.43.0
open377998No2415.43737982415.43.0
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See also

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+ © 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
+ https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog +

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