Countdown web component

A progressively enhanced <count-down> custom element that counts down to a specified date.

Demo.

Installation

Self hosted

Add the following to an HTML document:

<script type="module" src="path/to/countdown.js"></script>

CDN

Add the following to an HTML document:

<script type="module" src="https://unpkg.com/count-down-web-component@0.1.0/lib/countdown.js"></script>

NPM

Run npm i count-down-web-component.

Usage

First create a <count-down> element with default content for users of browsers that don't support web components:

<count-down>
  <h2 slot="heading">Doors open in</h2>
  <time>2019-06-01</time>
</count-down>

If the text content of the <time> element isn't a valid string, a datetime attribute must be added containing a valid string as its value.

Then add attributes to control the end date of the countdown and its layout breakpoints.

<count-down ends="2019-06-01" breakpoint1="25em" breakpoint2="50em">
  <h2 slot="heading">Doors open in</h2>
  <time>2019-06-01</time>
</count-down>

Attributes

ends - The date, and optional time, the countdown will end at. Must be one of the following formats from https://html.spec.whatwg.org/multipage/text-level-semantics.html#datetime-value:

• valid date string
• valid local date and time string
• valid global date and time string
• Four or more ASCII digits, at least one of which is not U+0030 DIGIT ZERO (0)

breakpoint1 - The days, hours, minutes and seconds are displayed in a single column CSS grid. This attribute sets the min-width media query where it goes to two columns.

breakpoint2 - This attribute sets the min-width media query where the grid goes to four columns.

All attributes can be updated programatically, and the UI will update to reflect the changes.

const clock = document.querySelector('count-down');
clock.ends = '2022-05-10';
clock.breakpoint1 = '100rem';
clock.breakpoint2 = '800px';

Styling

The <count-down> element can be styled using a universal, element, class, id or attribute selector as normal. Inherited properties will also work inside its shadow DOM e.g. font-family and color.

Two custom properties are available to set the font-size of the numbers and their units:

--countdown-number-font-size

--countdown-unit-font-size

Don't forget styles for the default experience!

License

MIT License