https://vsuo.cz/templates/webpage/js/tmstickup.js

1(function($,undefined){
2	var 
3		def={
4			stuckClass:'isStuck'			
5		}
6		,doc=$(document)
7
8	$.fn.TMStickUp=function(opt){
9		opt=$.extend(true,{},def,opt)
10
11		$(this).each(function(){
12			var $this=$(this)
13				,posY//=$this.offset().top+$this.outerHeight()
14				,isStuck=false
15				,clone=$this.clone(true,true).appendTo($this.parent()).addClass(opt.stuckClass)
16				,height//=$this.outerHeight()
17				,stuckedHeight=clone.outerHeight()
18				,opened//=$.cookie&&$.cookie('panel1')==='opened'
19				,tmr
20
21			$(window).resize(function(){
22				clearTimeout(tmr)				
23				clone.css({top:isStuck?0:-stuckedHeight,visibility:isStuck?'visible':'hidden'})
24
25				tmr=setTimeout(function(){
26					posY=$this.offset().top//+$this.outerHeight()				
27					height=$this.outerHeight()
28					stuckedHeight=clone.outerHeight()
29					opened=$.cookie&&$.cookie('panel1')==='opened'
30
31					clone.css({top:isStuck?0:-stuckedHeight})
32				},40)
33			}).resize()
34
35			clone.css({
36				position:'fixed'
37				,width:'100%'
38			})
39
40			$this
41				.on('rePosition',function(e,d){
42					if(isStuck)
43						clone.animate({marginTop:d},{easing:'linear'})
44
45					if(d===0)
46						opened=false
47					else
48						opened=true
49				})
50			
51			doc
52				.on('scroll',function(){
53					var scrollTop=doc.scrollTop()
54
55					if(scrollTop>=posY&&!isStuck){		
56								
57						clone
58							.stop()
59							.css({visibility:'visible'})
60							.animate({
61								top:0
62								,marginTop:opened?50:0
63							},{complete:function(){
64
65			}
66							})
67							
68						isStuck=true
69					}
70					
71					if(scrollTop<posY+height&&isStuck){
72						clone
73							.stop()
74							.animate({
75								top:-stuckedHeight
76								,marginTop:0
77							},{
78								duration:200
79								,complete:function(){
80									clone.css({visibility:'hidden'})
81								}
82							})
83												
84						isStuck=false
85					}			
86				})				
87				.trigger('scroll')
88		})
89	}
90})(jQuery)