jQuery toggleClass

You can extend jQuery to swap classes with a toggleClass as shown below:

//extend jquery
(function($) {
    $.fn.toggleClass = function(check, replace) {
        return this.each(function() {
            if ($(this).hasClass(check)) {
                $(this).removeClass(check);
                $(this).addClass(replace);
            } else {
                if ($(this).hasClass(replace))
                    $(this).removeClass(replace);
                $(this).addClass(check);
            }
        });
    };
})(jQuery);
  

So you can do stuff like this:

<input type="button" value="Toggle" 
onclick="$('#myDiv').toggleClass('expanded','collapsed')"/>