jquery-returnClassPrefix.js

/**
 * author: andreas johan virkus
 * snippet url: https://gist.github.com/andreasvirkus/917a47fd8276be57300e
 * 
 * Return all classes found that match the given prefix
 * Example: You have an element with classes "apple juiceSmall juiceBig banana"
 * You run:
 *   $elem.returnClassPrefix('juiceS');
 * The resulting class is "juiceSmall"
 *
 * @return {Array} List consists of a concatenated string of classes that match the prefix per element iterated
 */
$.fn.returnClassPrefix = function (prefix) {
    var matchedClasses = [];

    this.each( function ( i, it ) {
        var classes = it.className.split(' ').map(function (item) {
            return item.indexOf(prefix) === 0 ? item : '';
        });
        matchedClasses.push(classes.join(' ').trim());
    });

    return matchedClasses;
};