document.addEventListener('DOMContentLoaded', function (){ 
var $root = document.documentElement; 
var toTravel = $root.scrollHeight - window.innerHeight; 
var $bsaShadow = document.getElementById('bsaShadow'); 
var menuThrottle = null ; 
if ($bsaShadow) { 
document.addEventListener('scroll', function (event){ 
clearTimeout(menuThrottle); 
throttle = _AN_Call_settimeout('setTimeout', window, setBsaShadows(), 100); 
} 
); 
function setBsaShadows(){ 
var scrollTop = window.scrollY; 
var distance = toTravel - scrollTop; 
var topFactor = 1 - (distance / toTravel); 
$bsaShadow.style.opacity = topFactor; 
$bsaShadow.style.transform = 'scaleY(' + topFactor + ')'; 
} 
setBsaShadows(); 
} 
} 
);