objectFitPolyfill

object-fit-polyfill

A polyfill for browsers that don't support the object-fit CSS property. Unsure of what the object-fit does? Essentially object-fit is to <img> tags what background-size is to background-image. You can check out the MDN page for more details.

Features

• Works with img, picture, srcset, video, and canvas
• Supports object-position
• Supports IE 9+, Edge 18-, iOS 7-, and Android 4.4-
• Lightweight
  • 3KB (2KB with the basic version)
  • No dependencies: vanilla Javascript (works with or without jQuery)
• Flexible usage
  • Drop in an HTML script tag on a static page
  • Or import it into your modern JS SPA (Typescript supported)

Requirements

• This plugin requires setting data attributes on elements that you want polyfilled (data-object-fit).
• This plugin makes the assumption that the parent container is acting as a picture frame - it must have a height & width set.

Demo

You can check out the bare-bones demo here. Note that the plugin simply won't do anything if you're on a browser that already supports object-fit, so you'll want to test it on IE or older iOS/Android browsers.

How does it work?

Unlike object-fit-images or Primož Cigler's method (both excellent alternatives if you'd rather not use this one), this polyfill does not set a background image on the parent container, but instead resizes and repositions the image (using inline CSS for height, width, absolute positioning, and negative margins).

The polyfilled item will receive the class object-fit-polyfill if styling issues occur that require overrides.

Why bother?

If you're wondering: why bother using <img> tags versus background-image? Here's a couple reasons:

1. <img> tags have better SEO/crawling visibility.
2. In cases where images are dynamically returned and can't simply be added to your stylesheets (e.g., CMS's), you're forced to inline your background-image. This solves that somewhat-ugly-looking inline CSS.
3. background-image doesn't work with picture, video, or canvas elements.

Of course, there's still plenty of cases where using a background image makes more sense than a regular image.

Usage

Initialization:

<!-- Minimum CSS -->
<style>
  .container {
    width: 25em; /* Or whatever you want it to be */
    height: 25em; /* Or whatever you want it to be */
  }
  .media {
    width: 100%;
    height: 100%;
    object-fit: cover; /* Or whatever object-fit you want */
  }
</style>

<!-- Minimum HTML -->
<div class="container">
  <img
    alt=""
    src="https://unsplash.it/800/600/"
    class="media"
    data-object-fit="cover"
  />
</div>

<script src="dist/objectFitPolyfill.min.js"></script>

Customized object-fit/object-position:

<div class="container">
  <img
    alt=""
    src="https://unsplash.it/800/600/"
    class="media"
    data-object-fit="contain"
    data-object-position="top left"
  />
</div>

<div class="container">
  <img
    alt=""
    src="https://unsplash.it/800/600/"
    class="media"
    data-object-fit="none"
    data-object-position="25% 75%"
  />
</div>

<div class="container">
  <img
    alt=""
    src="https://unsplash.it/800/600/"
    class="media"
    data-object-fit="scale-down"
    data-object-position="3em -1em"
  />
</div>

If you're only interested in using the basic polyfill (which assumes object-fit: cover and object-position: 50% 50%), you can save yourself some bytes by using:

<div class="container">
  <img
    alt=""
    src="https://unsplash.it/800/600/"
    class="media"
    data-object-fit
  />
</div>

<script src="dist/objectFitPolyfill.basic.min.js"></script>

Advanced usage

If you need to dynamically call the polyfill on the fly for any reason (for example, carousels or lazy-loaded images), you can do so quite easily:

// Rerun the polyfill on all elements with the data attribute
objectFitPolyfill();

// Rerun the polyfill on a single DOM node
var element = document.querySelector('.foo');
objectFitPolyfill(element);

// Rerun the polyfill on multiple elements
var elements = document.querySelectorAll('.bar');
objectFitPolyfill(elements);

// Rerun the polyfill with a jQuery selector
objectFitPolyfill($('.baz'));

Installation via package managers

If you prefer not to manually add Javascript files to your sites, you can use bower and npm like so:

npm install objectFitPolyfill
yarn add objectFitPolyfill
# Or:
bower install objectFitPolyfill

Usage within a modern ES6/webpack JS project

import 'objectFitPolyfill';
// Or:
require('objectFitPolyfill');

window.objectFitPolyfill();

Note that in SPA's, you must manually call window.objectFitPolyfill() after component mount / once you're sure your media is loaded in & available. See this example React usage.

Requests?

If you'd like to make feature requests such as IE 8- or adding object-position support for Safari, feel free to open an issue or pull request! It's doable and on my radar, but I probably won't get to it without some prodding.