jQuery Ajax Rater Plugin is great work. I want 'callback' option for data from server. Is it useless?

 * Valid options:
 * ---------------------------------------
 *       style:       'basic', 'inline' OR 'small'
 *       maxvalue:    the maximum value / number of stars
 *       curvalue:    the initial value / selected stars
 *       callback:    function for data from server <-this

jQuery.fn.rater = function(url, options)
{
	if(url == null) return;
	var settings = {
		url       : url, // post changes to 
		maxvalue  : 5,   // max number of stars
		curvalue  : 0,   // number of selected stars
		callback  : null //=========================== test-settings.callback 
	};
	
	
	(Omission)

		if(settings.maxvalue == 1) // on / off
		{
			settings.curvalue = (settings.curvalue == 0) ? 1 : 0;
			jQuery(container).find('.star-rating').children('.current-rating')
				.css({width:(settings.curvalue*100)+'%'});
			jQuery.post(container.url, { "rating": settings.curvalue });
			return false;
		}
		else
		{
			settings.curvalue = stars.index(this) + 1;
			raterValue = jQuery(this).children('a')[0].href.split('#')[1];
			jQuery.post(container.url, { "rating": raterValue },
			
				//=====test-settings.callback 
				settings.callback ||
				function(response){
					container.children('.star-rating-result')
					         .html(response)
				}
			);
			return false;
		}

This is Original operation.

Add callback, curvalue is from server.

$(function (){

  function starRater(res){
	$('#vote1').empty().rater(
		'./ratingsdemo.php', {
			maxvalue : 5, 
			style    : 'basic', 
			curvalue : res||0,
			callback : starRater
	});
  }
  starRater(0);//An initial curvalue is 0. 
  
});

<?php echo($ratingData); ?>

	$('#vote1').empty().rater(
		'./ratingsdemo.php', {
			maxvalue : 5, 
			style    : 'basic', 
			curvalue : 3,
			callback : starRater
	});

Object data from server, and make HTML in callback function.

$(function (){

  function starRater(res){
	$('#vote2').empty().rater(
		'./ratingsdemo2.php', {
			maxvalue : 5, 
			style    : 'basic', 
			curvalue : res||0,
			callback : function(resoj){
			
				eval("var oj="+resoj);
				
				starRater(oj.Average);
				
				$('#vote2').children('.star-rating-result').html(
					oj.message 
					+"<br>Your click is : "+oj.myrate
					+"<br>Average is : "+oj.Average 
				);
				
			}
	});
  }
  starRater(0);
  
});

{ 
	myrate	: <?php echo($ratingData); ?>,
	Average	: 3, #for example result from SQL
	message	: "Hello rate!"
}