https://www.krumbach-noe.at/system/web/GetDocument.ashx?fileid=1165159&cts=1494408685

1	// Header fixieren
2	function sticky()
3		{
4			var window_top=$(window).scrollTop();
5			var top_position=$('body').offset().top;
6			var element_to_stick=$('#header');
7			if (window_top > top_position) {
8				element_to_stick.addClass('stuck');
9			} else {
10				element_to_stick.removeClass('stuck');
11			}
12		}
13		
14	// jQuery Start 
15	jQuery(document).ready(function($){
16		var proofcss = $('head').html().indexOf('presentation.css') > -1;
17		var proofcontrast =$('head').html().indexOf('highcontrast.css') > -1;			
18		if (proofcss) // Code für Standard Ansicht
19		{
20			// Body Klasse ergänzen
21			$('body').addClass('nview');
22
23			// Header fixieren
24			$(window).unbind('scoll');
25			$(window).off('scroll').on('scroll', function(e) {
26				sticky();
27			});		
28			
29		} 
30		else	// Code nur-Text Ansicht
31		{
32			$('body').removeClass().addClass('toview');
33		}
34		
35		if (proofcontrast) // Code hohe Kontrast Ansicht
36		{
37			$('body').removeClass().addClass('hcview');
38		}
39		else
40		{
41		}	
42	});