sortElements

    /**
     * jQuery.fn.sortElements
     * --------------
     * @param Function comparator:
     *   Exactly the same behaviour as [1,2,3].sort(comparator)
     *
     * @param Function getSortable
     *   A function that should return the element that is
     *   to be sorted. The comparator will run on the
     *   current collection, but you may want the actual
     *   resulting sort to occur on a parent or another
     *   associated element.
     *
     *   E.g. $('td').sortElements(comparator, function(){
     *      return this.parentNode;
     *   })
     *
     *   The <td>'s parent (<tr>) will be sorted instead
     *   of the <td> itself.
     */
    jQuery.fn.sortElements = (function(){

        var sort = [].sort;

        return function(comparator, getSortable) {

            getSortable = getSortable || function(){return this;};

            var placements = this.map(function(){

                var sortElement = getSortable.call(this),
                    parentNode = sortElement.parentNode,

                    // Since the element itself will change position, we have
                    // to have some way of storing its original position in
                    // the DOM. The easiest way is to have a 'flag' node:
                    nextSibling = parentNode.insertBefore(
                        document.createTextNode(''),
                        sortElement.nextSibling
                    );

                return function() {

                    if (parentNode === this) {
                        throw new Error(
                            "You can't sort elements if any one is a descendant of another."
                        );
                    }

                    // Insert before flag:
                    parentNode.insertBefore(this, nextSibling);
                    // Remove flag:
                    parentNode.removeChild(nextSibling);

                };

            });

            return sort.call(this, comparator).each(function(i){
                placements[i].call(getSortable.call(this));
            });

        };

    })();