ntz infinite carousel

ntzInfiniteCarousel.js

(function( $ ){
	$.fn.ntz_infiniteCarousel = function() {
		return this.each(function(){
			var carousel = $(this),
					etalon = $('li:first', carousel);

			carousel.wrap('<div class="ntz_infiniteCarouselWrap"></div>');

			var w = carousel.closest('.ntz_infiniteCarouselWrap'), //the wrap
					n = $('<a href="#" class="nav prev"/><a href="#" class="nav next"/>'), // the navigation
					inc = etalon.outerWidth(true), // increment - the width of an element ( is the same amount of px to be scrolled )
					ul = $('ul', carousel),
					perPage = Math.ceil( w.width()/inc ), // how many elements are displayed per page
					fX = $('li:lt(' + perPage + ')', ul).clone(), // first and last X elements ( x = perPage)
					lX = $('li:gt('+ ( $('li', ul).length - perPage-1 ) +')', ul).clone(),
					s = $('li.s', carousel); // selected 
			w.addClass( carousel.attr('id') );

			ul.append(fX).prepend(lX); // adding elemnts on begining and the end for infinite loop

			var	ulW = $('li', ul).length * inc, // width for ul
					maxPos = -1*(ulW - inc*perPage - perPage); // max position
			ul.width( ulW ).css({marginLeft:-inc*perPage}); 

			if( s.length ){
				ul.css({ marginLeft:-s.index()*inc + inc});
			}

			n.click(function(){
				var t = $(this),
						curPos = parseInt(ul.css('marginLeft'), 10);

				if( ul.is(':animated') ) {return false;} // we don't need multiple scrolls

				if( t.hasClass('prev') ){ // scroll left
					if( curPos >= 0 ){
						ul.css({ marginLeft: -( ulW - inc * perPage*2 ) }); // infinite loop
					}
					ul.animate({ marginLeft:'+='+inc })
				}

				if ( t.hasClass('next') ) { //scroll right
					if( maxPos >= curPos ){
						ul.css({ marginLeft: - inc * perPage }); // infinite loop
					}
					ul.animate({ marginLeft:'-='+inc });
				}			
				return false;
			});
			n.appendTo(w);


		});
	}; // ntz_infiniteCarousel
})( jQuery );

$('#infinity').ntz_infiniteCarousel();