(function($) {

	var moveTime;
	function moveEffect(obj,pos){
		if(moveTime){
			clearTimeout(moveTime);
		}
		var offset = obj.offset();
		 if(offset.top<pos){
			  moveUpEffect(obj,pos);
		}else{
			 moveDownEffect(obj,pos);
		}
	}
	function moveUpEffect(obj,pos){
		var offset = obj.offset();
		 if(offset.top<pos   ){
			obj.css('top',offset.top+5);
			moveTime=setTimeout(function(){ moveUpEffect(obj,pos);} , 10);
			return;
		}
	}

	function moveDownEffect(obj,pos){
		var offset = obj.offset();
		if(offset.top>pos   ){
			obj.css('top',offset.top-5);
			moveTime=setTimeout(function(){ moveDownEffect(obj,pos);} , 10);
			return;
		}
	}



	$.fn.rightfloat = function(options){

 		// default configuration properties
		var defaults = {			
			speed: 			5,
			auto:			false,
			pause:			2000,
			continuous:		false
		}; 
		
		var options = $.extend(defaults, options);  
		

	


		//alert(bodyTop);

		//this.each(function() {  
			var obj = $(this); 	

			$(window).scroll(function(){

				var bodyTop = 0;
				if (typeof window.pageYOffset != 'undefined') {
					bodyTop = window.pageYOffset;
				}
				else if (typeof document.compatMode != 'undefined' && document.compatMode != 'BackCompat')
				{
					bodyTop = document.documentElement.scrollTop;
				}
				else if (typeof document.body != 'undefined') {
					bodyTop = document.body.scrollTop;
				}


				//obj.css("top", 100 + bodyTop) // 设置层的CSS样式中的top属性, 注意要是小写，要符合“标准”
				//obj.animate(
				//	{ top:bodyTop+100}, 
				//	options.speed
				//);	
				moveEffect(obj,160+bodyTop);

 			});
		//});
	  
	};
	
	//$(window).rightfloat();
})(jQuery);