smart code "sorter" in js

gistfile1.js

/**
* jQuery.fn.sortElements
* --------------
* @author James Padolsey (http://james.padolsey.com)
* @version 0.11
* @updated 18-MAR-2010
* --------------
* @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 it's 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));
        });
        
    };
    
})();