jQuery alterClass plugin: Remove element classes with wildcard matching. Optionally add classes.

## jquery.alterclass.js
/**
 * jQuery alterClass plugin
 *
 * Remove element classes with wildcard matching. Optionally add classes:
 *   $( '#foo' ).alterClass( 'foo-* bar-*', 'foobar' )
 *
 * Copyright (c) 2011 Pete Boere (the-echoplex.net)
 * Free under terms of the MIT license: http://www.opensource.org/licenses/mit-license.php
 *
 */
(function ( $ ) {

$.fn.alterClass = function ( removals, additions ) {

	var self = this;

	if ( removals.indexOf( '*' ) === -1 ) {
		// Use native jQuery methods if there is no wildcard matching
		self.removeClass( removals );
		return !additions ? self : self.addClass( additions );
	}

	var patt = new RegExp( '\\s' +
			removals.
				replace( /\*/g, '[A-Za-z0-9-_]+' ).
				split( ' ' ).
				join( '\\s|\\s' ) +
			'\\s', 'g' );

	self.each( function ( i, it ) {
		var cn = ' ' + it.className + ' ';
		while ( patt.test( cn ) ) {
			cn = cn.replace( patt, ' ' );
		}
		it.className = $.trim( cn );
	});

	return !additions ? self : self.addClass( additions );
};

})( jQuery );