ModalBackdrop

Semi-transparent backdrop for a modal overlay

Here's a dialog.

This paragraph has a z-index, but should appear behind the dialog. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse sed lorem scelerisque, blandit libero vitae, dapibus nisl. Sed turpis diam, placerat a feugiat sed, maximus at velit. Ut sit amet semper sapien. Donec vitae leo ex. Duis eget quam sed metus tempor lobortis eget feugiat elit. Cras varius, arcu ac commodo tincidunt, lectus dui convallis nunc, quis maximus nisl erat ac mi. Phasellus et velit diam.

Demo: A ModalBackdrop appears behind a Dialog to partially obscure the background

Overview

ModalBackdrop is a simple backdrop for a modal overlay such as a Dialog or Drawer. The backdrop slightly obscures the background elements, focusing the user's attention on the overlay. It also contributes to the modality by absorbing background clicks.

See also

Backdrop
Background element shown behind an overlay's primary content
Dialog
Basic modal overlay that the user typically dismisses with an explicit action

API

Ancestry: ModalBackdrop → BackdropReactiveElement → HTMLElement

Built with mixins AriaRoleMixin, AttributeMarshallingMixin, ReactiveMixin, and ShadowTemplateMixin.

This element is used to fill a role in AlertDialog, Dialog, and Drawer.

$ property

A convenient shortcut for looking up an element by ID in the component's Shadow DOM subtree.

Example: if component's template contains a shadow element <button id="foo">, you can use the reference this.$.foo to obtain the corresponding button in the component instance's shadow tree. The $ function is simply a shorthand for getElementById, so this.$.foo is the same as this.shadowRoot.getElementById('foo').

Type: object

Defined by ShadowTemplateMixin

defaultState property

The default state for the component. This can be extended by mixins and classes to provide additional default state.

Type: State

Defined by ReactiveMixin

render() method

Render pending component changes to the DOM.

This method does nothing if the state has not changed since the last render call.

This method invokes all internal render methods. It then invoked componentDidMount (for first render) or componentDidUpdate (for subsequent renders).

Defined by ReactiveMixin

setState(changes) method

Update the component's state by merging the specified changes on top of the existing state. If the component is connected to the document, and the new state has changed, this returns a promise to asynchronously render the component. Otherwise, this returns a resolved promise.

Parameters:

  • changes: objectthe changes to apply to the element's state

Returns: Promise - resolves when the new state has been rendered

Defined by ReactiveMixin

state property

The component's current state. The returned state object is immutable. To update it, invoke setState.

Type: State

Defined by ReactiveMixin

[symbols.render](changed) method

Internal method for rendering any recent changes in state to the DOM.

The default implementation of this method does nothing. Override this method in your component to update your component's host element and any shadow elements to reflect the component's new state. See the rendering example.

Be sure to call super in your method implementation so that your component's base classes and mixins have a chance to perform their own render work.

Parameters:

  • changed: objectdictionary of flags indicating which state members have changed since the last render

Defined by ReactiveMixin