Fork of boaz’s jQuery.fn.classList() method with some minor improvements

jQuery.classList.js

/*
Usages:
$(selector).classList() // returns an array of classnames
$(selector).classList('newclass') // replaces the current element’s classes
$(selector).classList(['new', 'class', 'names']) // replaces the current element’s classes
*/

jQuery.fn.extend({
 classList: function(value) {
  if (value) {
   if (jQuery.isArray(value)) {
    this.attr('class', value.join(' '));
    return this;
   } else if (typeof value === 'string') {
    return this.attr('class', value);
   };
  };
  return this.attr('class').split(/\s+/);
 }
});