//You need an anonymous function //to wrap around your function to avoid conflict  
(function($) {
		
	$.fn.extend( {

		dropdown : function(menu_id, options) {

			var defaults = {
				show_duration: 500,
				hide_duration: 500
			};  
			
			var options =  $.extend(defaults, options); 
		
			return this.each(function() {					
				var o = options;				
				var obj = $(this);
				var _id = this.id;
				var _name = this.name;
				
				var position = obj.offset();
				var height = obj.outerHeight();
				var width = obj.outerWidth();
				var menu_obj = $('#' + menu_id);
				menu_obj.css('display', 'none');
				menu_obj.css('position', 'absolute');
				menu_obj.css('left', (position.left) + 'px');
				menu_obj.css('top', (position.top - menu_obj.height()) + 'px');
				
				obj.mouseout(function(event) {
					 menu_obj.hide();
					 obj.removeClass('menu-dropdown-selected');
					this.blur();
				});
				
				obj.mouseover(function(event){
					
//					if(menu_obj.is(':visible')){
//						menu_obj.fadeOut(o.hide_duration);						
//						$(this).removeClass('menu-dropdown-selected');		
//						this.blur();
//					}else{
						menu_obj.show();
						$(this).addClass('menu-dropdown-selected');
						this.blur();
//					}
					
//					event.stopPropagation();
				});
				
				
				
			});
		}
	
	});
	
})(jQuery);