Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Tiny and powerful module loader to lazy load HTML+CSS+JS
JavaScript
branch: master

Fetching latest commit…

Cannot retrieve the latest commit at this time

Failed to load latest commit information.
demo
README.md
duck.js
rsvp.amd.js
rsvp.js

README.md

DuckJS

Motivation

Often do I identify the need to fetch only a minimum of resources on page load, in order to optimize perceived performance. All resources that are not required immediately should then be lazy loaded on demand. This tiny library provides the means to do just that.

There are not a lot of complete solutions to (lazy) load complete modules (i.e. JavaScript, and CSS, and HTML) in a simple and straightforward manner. Script loaders are common, but they usually support only JavaScript.

yepnope

Why develop or use DuckJS when there is yepnope? The popular (and deservedly so!) yepnope library is a similar solution, but DuckJS has an even simpler API, is much smaller, and supports both CSS and HTML loading by default. On the other hand, DuckJS doesn't have the yep/nope feature tests for conditional resource loading, and also there is no plugin architecture. This is by design, to keep things simple.

API

Duck.load({
    content: 'module.html',
    contentAppend: document.getElementById('modulePlaceholder'),
    css: 'module.css',
    script: 'module.js',
    callback: function(){}
});

Every option is optional.

Arrays can be provided to load multiple CSS or script resources, e.g.:

Duck.load({
    content: 'module.html',
    contentAppend: document.getElementById('modulePlaceholder'),
    css: ['module.css', 'module-more.css'],
});

Features

  • Fast & small (under 1K when minified/gzipped)
  • Simple API
  • Parses CSS before HTML is inserted (to prevent from FOUC)
  • Execute module script asynchronously (and callback function at the end)
  • Supports IE7+
  • Supports AMD

Notes

  • HTML content is fetched using XMLHttpRequest, which (apart from a CORS setup) does not support cross-domain requests.
  • Stylesheets and scripts are loaded using their normal <link> and <script> elements and can be cross-domain.
  • Any HTML content is simply set using innerHTML on the provided contentAppend argument property.
  • Duck has a dependency to the small but excellent RSVP.js for using promises (to deal with async requests).

Credits

Many thanks to Spil Games for allowing me to open source this and develop it further during working hours.

Lots of thanks go to the inspiritational likes of:

Something went wrong with that request. Please try again.