DOM Elements
=============

DOM Elements is a polyfill that allows you to use the `.query` and `.queryAll`
methods newly added to [the DOM Standard]. `queryAll` returns an instance of the
new [Elements class] which extends Array, allowing you to use map, reduce,
filter, forEach, and the like on the returned elements.

[Elements class]: http://dom.spec.whatwg.org/#collections:-elements
[the DOM Standard]: http://dom.spec.whatwg.org

[![The DOM Elements polyfill supports Internet Explorer 9+, Chrome 15.0+, Firefox 4.0+, Opera 12.0+, Safari 5.0.5+, Mobile Safari 6.0+.](https://ci.testling.com/barberboy/dom-elements.png)](https://ci.testling.com/barberboy/dom-elements)

Background
----------

The DOM Standard added [query] and [queryAll] methods to the ParentNode
interface, which is implemented by  Document, Element, and DocumentFragment. It
also defined a new class, [Elements], which extends Array and also has query and
 queryAll.

[Elements]: http://dom.spec.whatwg.org/#collections:-elements
[query]: http://dom.spec.whatwg.org/#dom-parentnode-query
[queryAll]: http://dom.spec.whatwg.org/#dom-parentnode-queryall

Usage
-----

You can install the `dom-elements` package with either npm or bower, or directly
download [dom-elements.js] or [dom-elements.min.js] and include them in your
project.

    bower install dom-elements

or

    npm install dom-elements

[dom-elements.js]: https://raw.githubusercontent.com/barberboy/dom-elements/0.1.0/lib/dom-elements.js
[dom-elements.min.js]: https://raw.githubusercontent.com/barberboy/dom-elements/0.1.0/lib/dom-elements.min.js

You are also welcome to clone the repo directly and use the dom-elements.js or
dom-elements.min.js in the `lib` directory.

    git clone https://github.com/barberboy/dom-elements
    npm install
    npm start

### .query(relativeSelector)

`.query()` is available on document, documentFragments, individual DOM elements,
and the Elements class. It will return the first descendant element which
matches the selector, or null if there are zero matches.

    var siteHeader = document.query('header');
    if (siteHeader) {
      var active = siteHeader.query('.site-menu .active');
    }

### .queryAll(relativeSelector)

.queryAll is available on document, documentFragments, individual DOM elements
and the Elements class. It will return a new instance of Elements containing
descendants that match the passed selector, or an instance with no elements if
there are no matches.

    var collapsibles = document.queryAll('.collapsible');
    collapsibles.forEach(function(collapsible){
      var heading = collapsible.query('h1,h2,h3,h4,h5,h6');
      heading.addEventListener('click', function(event) {
        collapsible.classList.toggle('collapsed');
      }, false);
    });

    // .query and .queryAll are available on the Elements array as well.
    var sections = document.queryAll('section');
    var headingLinks = sections.queryAll(':any(h1,h2,h3,h4,h5,h6) a');

Caveats
-------

* Since we use querySelectorAll and ES5 Array methods, this shim will not work
  in IE8 and below. See the browser support list at
  <https://ci.testling.com/barberboy/dom-elements>.
* This shim (despite it's name—ha!) does not expose the Elements constructor
  function since there isn't a compelling use-case for instantiating it
  directly.
* **Update:** Support for [Relative Selectors] was added in version
  [0.1.0][issue #2] by @bloodyowl.

[Relative Selectors]: http://dev.w3.org/csswg/selectors/#relative
[issue #2]: https://github.com/barberboy/dom-elements/issues/2

License
-------
MIT