Shadowbox

Motivation

Dialog boxes are such a common design pattern that they need no explanation. HTML5 has a special dialog tag for that very purpose. Unfortunately, the HTML dialog tag does not provide any "standard" behavior for how it should appear. Nor does it provide a convenient way for the user to dismiss it.

The rwt-shadowbox DOM component has several features which overcome those limitations, and make for a more pleasant user experience.

• The dialog box has a titlebar with caption and close button.
• The contents may be slotted or provided with a template file.
• The dialog has an event interface for showing and hiding itself.
• The dialog emits a custom event to close sibling dialog boxes.
• A keyboard listener is provided to allow a shortcut key to open/close the dialog.

In the wild

To see an example of this component in use, visit the READ WRITE TOOLS website and press F2 "Info" or F3 "Rights". To understand what's going on under the hood, use the browser's inspector to view the HTML source code and network activity, and follow along as you read this documentation.

Installation

Prerequisites

The rwt-shadowbox DOM component works in any browser that supports modern W3C standards. Templates are written using BLUEPHRASE notation, which can be compiled into HTML using the free Read Write View desktop app. It has no other prerequisites. Distribution and installation are done with either NPM or via Github.

Download

npm install rwt-shadowbox
							

Using the DOM component

After installation, you need to add four things to your HTML page to make use of it.

• Add a script tag to load the component's rwt-shadowbox.js file:

<script src='/node_modules/rwt-shadowbox/rwt-shadowbox.js' type=module></script>             
							

• Add the component tag somewhere on the page.
• For scripting purposes, apply an id attribute.
• Apply a titlebar attribute with the text you want to appear as a caption.
• Optionally, apply a shortcut attribute with something like F1, F2, etc. for hotkey access.
• Optionally, apply a sourceref attribute with a reference to an HTML file containing the dialog's text and any CSS it needs.
• And for WAI-ARIA accessibility apply a role=contentinfo attribute.
• For simple dialog boxes, the sourceref may be omitted and the text of the dialog box may be slotted into the DOM component. Simply place the text directly between the <rwt-shadowbox> and </rwt-shadowbox> tags.

<rwt-shadowbox id=info titlebar=Info shortcut=F1 sourceref='/info.blue' role=contentinfo ></rwt-shadowbox>
							

• Add a way for the visitor to show the dialog:

<a id='info-button' title="Info (F1)">ℹ</a>
							

• Add a listener to respond to the click event:

<script type=module>
    document.getElementById('info-button').addEventListener('click', (e) => {
        document.getElementById('info').toggleDialog(e);
    });
</script>
							

Customization

Dialog size and position

The dialog is absolutely positioned towards the bottom left of the viewport. Its size may be overridden using CSS by defining new values for the size and position variables.

rwt-shadowbox#info {
    --min-width: 10rem;
    --optimal-width: 70vw;
    --max-width: 40rem;
    
    --min-height: 10rem;
    --optimal-height: 50vh;
    --max-height: 40rem;

    --bottom: 1rem;
    --left: 1rem;
    --z-index: 1;
}
						

Dialog color scheme

The default color palette for the dialog uses a dark mode theme. You can use CSS to override the variables' defaults:

rwt-shadowbox#info {
    --color: var(--white);
    --accent-color1: var(--yellow);
    --accent-color2: var(--js-blue);
    --background: var(--black);
    --accent-background1: var(--medium-black);
    --accent-background2: var(--pure-black);
    --accent-background3: var(--nav-black);
    --accent-background4: var(--black);
}
						

Life-cycle events

The component issues life-cycle events.

component-loaded

Sent when the component is fully loaded and ready to be used. As a convenience you can use the waitOnLoading() method which returns a promise that resolves when the component-loaded event is received. Call this asynchronously with await.

Event controllers

The dialog box can be controlled with its event interface.

toggle-shadowbox

The component listens on DOM document for toggle-shadowbox messages. Upon receipt it will show or hide the dialog box.

keydown

The component listens on DOM document for keydown messages. If the user presses the configured shortcut key (F1, F2, etc) it will show/hide the dialog box. The Esc key closes the dialog box.

collapse-popup

The component listens on DOM document for collapse-popup messages, which are sent by sibling dialog boxes. Upon receipt it will close itself.

click

The component listens on DOM document for click messages. When the user clicks anywhere outside the dialog box, it closes itself.

Reference

	Documentation	READ WRITE HUB
	Source code	github
	Component catalog	DOM COMPONENTS
	Package installation	npm
	Publication venue	READ WRITE STACK

License

The rwt-shadowbox DOM component is licensed under the MIT License.