Creating a simple jQuery plug-in

/*!
 * Map Scroller v1.0.0
 * A jQuery Plugin that makes any html element scrollable in a custom way.
 * Copyright 2010, Anand, Vijaya .M
 * Date: Thursday, September 18th 2010
 *
 * Usage:
 * 		$(selector).mapScroll(direction); //enable scrolling
 *					direction - which direction the scrolling is allowed
 * 								vertical, horizontal or both(default)   		
 *
 */
 
 
(function($){

	var eventHandlers = {
		mousemove: function(e){
			var $this = $(this), 
			    scroll = $this.data("scroll"), 
				prevPos = $this.data("position"),
				scrollFn = $this.data("scrollFn");
			
			if(scroll){			
				var diffX = prevPos.x - e.pageX, 
				    diffY = prevPos.y - e.pageY;
						
				scrollFn($this, diffX, diffY);
				
				$this.data("position", {x:e.pageX, y:e.pageY});
			}
		},
		
		mouseupout: function(e){
			$(this).data("scroll", false);
					
			$(this).removeClass("closedhand")
				   .addClass("openhand");
		},
		
		mousedown: function(e){						   
			$(this).data("scroll", true)
				   .data("position", {x : e.pageX, y : e.pageY});
				   
			$(this).removeClass("openhand")
				   .addClass("closedhand");				   
		}
	};
		
	$.fn.mapScroll = function(direction){

		//assigning scroll function
		var scrollFn = (function(){
			switch(direction || "both")
				{
					case "vertical":
						return function($this,x,y){ 
							$this.scrollTop( $this.scrollTop() + y ); 
						};
   				    case "horizontal":
						return function($this,x,y){ 
							$this.scrollLeft( $this.scrollLeft() + x ); 
						};
					case "both":
						return function($this,x,y){ 
							$this.scrollTop( $this.scrollTop() + y).scrollLeft($this.scrollLeft() + x );
						};				
				}		
		})();		
		
		return this.each(function(){
			//disabling text selection
			$(this).disableTextSelect();
			
			//binding event-handlers
			$(this).bind("mousemove", eventHandlers.mousemove)
				   .bind("mouseup mouseout", eventHandlers.mouseupout)
				   .bind("mousedown", eventHandlers.mousedown);
			
			//adding class
			$(this).addClass("openhand");	
			
			//caching the scroll function.
			$(this).data("scrollFn", scrollFn);			
		});
	};
		
})(jQuery);