<dialog>: The Dialog element

This element includes the global attributes.

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.

• HTML <form> elements can be used to close a dialog box if they have the attribute method="dialog" or if the button used to submit the form has formmethod="dialog" set. When a <form> within a <dialog> is submitted via the dialog method, the dialog box closes, the states of the form controls are saved but not submitted, and the returnValue property gets set to the value of the button that was activated.
• The CSS ::backdrop pseudo-element can be used to style the backdrop of a modal dialog, which is displayed behind the <dialog> element when the dialog is displayed using the HTMLDialogElement.showModal() method. For example, you can use this pseudo-element to obfuscate the inert content behind the modal dialog.
• The autofocus attribute should be added to the element with which the user is expected to interact immediately on opening a modal dialog. If there is no element involving immediate interaction, the autofocus attribute can be added to the <dialog> element itself.

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.

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

Result

This dialog is initially open because of the presence of the open attribute. Dialogs that are displayed using the open attribute are non-modal. 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.

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

<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.

::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.

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

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.

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

<!-- 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

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

The above examples demonstrate the following three methods of closing modal dialogs:

• By submitting the form within the dialog form using the dialog method (as seen in the HTML-only example).
• By pressing the Esc key.
• By calling the HTMLDialogElement.close() method (as seen in the modal example). In this example, the "Cancel" button closes the dialog via the dialog form method and the "Confirm" button closes the dialog via the HTMLDialogElement.close() method.

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).

<dialog>s are set to display: none; when hidden and display: block; when shown, as well as being removed from / added to the top layer and the accessibility tree. Therefore, for <dialog> elements to be animated the display property needs to be animatable. Supporting browsers animate display with a variation on the discrete animation type. Specifically, the browser will flip between none and another value of display so that the animated content is shown for the entire animation duration.

So for example:

• When animating display from none to block (or another visible display value), the value will flip to block at 0% of the animation duration so it is visible throughout.
• When animating display from block (or another visible display value) to none, the value will flip to none at 100% of the animation duration so it is visible throughout.

Transitioning dialog elements

When animating <dialog>s with CSS transitions, the following features are required:

@starting-style at-rule

Provides a set of starting values for properties set on the <dialog> that you want to transition from every time it is opened. This is needed to avoid unexpected behavior. By default, CSS transitions only occur when a property changes from one value to another on a visible element; they are not triggered on elements' first style updates, or when the display type changes from none to another type.

display property

Add display to the transitions list so that the <dialog> will remain as display: block (or another visible display value set on the dialog's open state) for the duration of the transition, ensuring the other transitions are visible.

overlay property

Include overlay in the transitions list to ensure the removal of the <dialog> from the top layer is deferred until the transition completes, again ensuring the transition is visible.

transition-behavior property

Set transition-behavior: allow-discrete on the display and overlay transitions (or on the transition shorthand) to enable discrete transitions on these two properties that are not by default animatable.

Here is a quick example to show what this might look like.

HTML

The HTML contains a <dialog> element, plus a button to show the dialog. Additionally, the <dialog> element contains another button to close itself.

<dialog id="dialog">
  Content here
  <button class="close">close</button>
</dialog>

<button class="show">Show Modal</button>

CSS

In the CSS, we include a @starting-style block that defines the transition starting styles for the opacity and transform properties, transition end styles on the dialog[open] state, and default styles on the default dialog state to transition back to once the <dialog> has appeared. Note how the <dialog>'s transition list includes not only these properties, but also the display and overlay properties, each with allow-discrete set on them.

We also set a starting style value for the background-color property on the ::backdrop that appears behind the <dialog> when it opens, to provide a nice darkening animation. The dialog[open]::backdrop selector selects only the backdrops of <dialog> elements when the dialog is open.

/*   Open state of the dialog  */
dialog[open] {
  opacity: 1;
  transform: scaleY(1);
}

/*   Closed state of the dialog   */
dialog {
  opacity: 0;
  transform: scaleY(0);
  transition:
    opacity 0.7s ease-out,
    transform 0.7s ease-out,
    overlay 0.7s ease-out allow-discrete,
    display 0.7s ease-out allow-discrete;
  /* Equivalent to
  transition: all 0.7s allow-discrete; */
}

/*   Before-open state  */
/* Needs to be after the previous dialog[open] rule to take effect,
    as the specificity is the same */
@starting-style {
  dialog[open] {
    opacity: 0;
    transform: scaleY(0);
  }
}

/* Transition the :backdrop when the dialog modal is promoted to the top layer */
dialog::backdrop {
  background-color: rgb(0 0 0 / 0);
  transition:
    display 0.7s allow-discrete,
    overlay 0.7s allow-discrete,
    background-color 0.7s;
  /* Equivalent to
  transition: all 0.7s allow-discrete; */
}

dialog[open]::backdrop {
  background-color: rgb(0 0 0 / 0.25);
}

/* This starting-style rule cannot be nested inside the above selector
because the nesting selector cannot represent pseudo-elements. */

@starting-style {
  dialog[open]::backdrop {
    background-color: rgb(0 0 0 / 0);
  }
}

JavaScript

The JavaScript adds event handlers to the show and close buttons causing them to show and close the <dialog> when they are clicked:

const dialogElem = document.getElementById("dialog");
const showBtn = document.querySelector(".show");
const closeBtn = document.querySelector(".close");

showBtn.addEventListener("click", () => {
  dialogElem.showModal();
});

closeBtn.addEventListener("click", () => {
  dialogElem.close();
});

Result

The code renders as follows:

dialog keyframe animations

When animating a <dialog> with CSS keyframe animations, there are some differences to note from transitions:

• You don't provide a @starting-style.
• You include the display value in a keyframe; this will be the display value for the entirety of the animation, or until another non-none display value is encountered.
• You don't need to explicitly enable discrete animations; there is no equivalent to allow-discrete inside keyframes.
• You don't need to set overlay inside keyframes either; the display animation handles the animation of the <dialog> from shown to hidden.

Let's have a look at an example so you can see what this looks like.

HTML

First, the HTML contains a <dialog> element, plus a button to show the dialog. Additionally, the <dialog> element contains another button to close itself.

<dialog id="dialog">
  Content here
  <button class="close">close</button>
</dialog>

<button class="show">Show Modal</button>

CSS

The CSS defines keyframes to animate between the closed and shown states of the <dialog>, plus the fade-in animation for the <dialog>'s backdrop. The <dialog> animations include animating display to make sure the actual visible animation effects remain visible for the whole duration. Note that it wasn't possible to animate the backdrop fade out — the backdrop is immediately removed from the DOM when the <dialog> is closed, so there is nothing to animate.

dialog {
  animation: fade-out 0.7s ease-out;
}

dialog[open] {
  animation: fade-in 0.7s ease-out;
}

dialog[open]::backdrop {
  animation: backdrop-fade-in 0.7s ease-out forwards;
}

/* Animation keyframes */

@keyframes fade-in {
  0% {
    opacity: 0;
    transform: scaleY(0);
    display: none;
  }

  100% {
    opacity: 1;
    transform: scaleY(1);
    display: block;
  }
}

@keyframes fade-out {
  0% {
    opacity: 1;
    transform: scaleY(1);
    display: block;
  }

  100% {
    opacity: 0;
    transform: scaleY(0);
    display: none;
  }
}

@keyframes backdrop-fade-in {
  0% {
    background-color: rgb(0 0 0 / 0);
  }

  100% {
    background-color: rgb(0 0 0 / 0.25);
  }
}

body,
button {
  font-family: system-ui;
}

JavaScript

Finally, the JavaScript adds event handlers to the buttons to enable showing and closing the <dialog>:

const dialogElem = document.getElementById("dialog");
const showBtn = document.querySelector(".show");
const closeBtn = document.querySelector(".close");

showBtn.addEventListener("click", () => {
  dialogElem.showModal();
});

closeBtn.addEventListener("click", () => {
  dialogElem.close();
});

Result

The code renders as follows:

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.

• HTMLDialogElement interface
• close event
• cancel event
• open property of the HTMLDialogElement interface
• inert global attribute for HTML elements
• ::backdrop CSS pseudo-element
• Web forms in the Learn area