NWMatcher

A fast CSS selector engine and matcher.

Installation

To include NWMatcher in a standard web page:

<script type="text/javascript" src="nwmatcher.js"></script>

To use it with Node.js:

$ npm install nwmatcher

NWMatcher currently supports browsers (as a global, NW.Dom) and headless environments (as a CommonJS module).

Supported Selectors

Here is a list of all the CSS2/CSS3 Supported selectors.

Features and Compliance

You can read more about NWMatcher features and compliance on the wiki.

API

DOM Selection

first( selector, context )

Returns a reference to the first element matching selector, starting at context.

match( element, selector, context )

Returns true if element matches selector, starting at context; returns false otherwise.

select( selector, context, callback )

Returns an array of all the elements matching selector, starting at context. If callback is provided, it is invoked for each matching element.

DOM Helpers

byId( id, from )

Returns a reference to the first element with ID id, optionally filtered to descendants of the element from.

byTag( tag, from )

Returns an array of elements having the specified tag name tag, optionally filtered to descendants of the element from.

byClass( class, from )

Returns an array of elements having the specified class name class, optionally filtered to descendants of the element from.

byName( name, from )

Returns an array of elements having the specified value name for their name attribute, optionally filtered to descendants of the element from.

getAttribute( element, attribute )

Return the value read from the attribute of element with name attribute, as a string.

hasAttribute( element, attribute )

Returns true element has an attribute with name attribute set; returns false otherwise.

Engine Configuration

configure( options )

The following options exist and can be set to true or false:

• CACHING: enable caching of results
• SHORTCUTS: allow accepting mangled selectors
• SIMPLENOT: disallow nested complex :not() selectors
• UNIQUE_ID: disallow multiple elements with same ID
• USE_QSAPI: enable native querySelectorAll if available
• USE_HTML5: enable special HTML5 rules, related to the relationship between :checked and :selected
• VERBOSITY: choose between throwing errors or just console warnings

Example:

NW.Dom.configure( { USE_QSAPI: false, VERBOSITY: false } );

registerOperator( symbol, resolver )

Registers a new symbol and its matching resolver in the operators table. Example:

NW.Dom.registerOperator( '!=', 'n!="%m"' );

registerSelector( name, rexp, func )

Registers a new selector, with the matching regular expression and the appropriate resolver function, in the selectors table.