(function($) {
	$.extend($.fx.step,{
	    backgroundPosition: function(fx) {
            if (fx.state === 0 && typeof fx.end == 'string') {
                var start = $.curCSS(fx.elem,'backgroundPosition');
                start = toArray(start);
                fx.start = [start[0],start[2]];
                var end = toArray(fx.end);
                fx.end = [end[0],end[2]];
                fx.unit = [end[1],end[3]];
			}
            var nowPosX = [];
            nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];
            nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];
            fx.elem.style.backgroundPosition = nowPosX[0]+' '+nowPosX[1];

           function toArray(strg){
               strg = strg.replace(/left|top/g,'0px');
               strg = strg.replace(/right|bottom/g,'100%');
               strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");
               var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
               return [parseFloat(res[1],10),res[2],parseFloat(res[3],10),res[4]];
           }
        }
	});
	
	$.fn.newsScroll = function(options) {
	
	// For each item in the wrapped set, perform the following. 
	return this.each(function() {	
	  
		var
		  // Caches this - or the ul widget(s) that was passed in.
		  //  Saves time and improves performance.
		  $this = $(this), 
		  
		  // If the user doesn't pass in parameters, we'll use this object. 
		  defaults = {
		  	speed: 400, // How quickly should the items scroll?
		  	delay: 3000, // How long a rest between transitions?
		  	list_item_height: $this.children('li').outerHeight() // How tall is each list item? If this parameter isn't passed in, jQuery will grab it.
	     },
	      // Create a new object that merges the defaults and the 
	      // user's "options".  The latter takes precedence.
		  settings = $.extend({}, defaults, options);
		 
	  // This sets an interval that will be called continuously.
	  setInterval(function() {
	  	    // Get the very first list item in the wrapped set.
	  	    $this.children('li:first')
	  	    		// Animate it
	  	    		.animate({ 
	  	    			marginTop : '-' + settings.list_item_height, // Shift this first item upwards.
	  	    		   opacity: 'hide' }, // Fade the li out.
	  	    		   
	  	    		   // Over the course of however long is 
	  	    		   // passed in. (settings.speed)
	  	    		   settings.speed, 
	  	    		   
	  	    		   // When complete, run a callback function.
	  	    		   function() {
	  	    		   	
	  	    		   	// Get that first list item again. 
	  	 					$this.children('li:first')
	  	 					     .appendTo($this) // Move it the very bottom of the ul.
	  	 					     
	  	 					     // Reset its margin top back to 0. Otherwise, 
	  	 					     // it will still contain the negative value that we set earlier.
	  	 					     .css('marginTop', 0) 
	  	 					     .fadeIn(300); // Fade in back in.
  		 			  }
 	 			  ); // end animate
 	  }, settings.delay); // end setInterval
	  });
}
})(jQuery);