(function() {
var elem = document.querySelector('.name'),
body = document.body,
html = document.documentElement;
window.addEventListener('scroll', function() {
var scrollHeight = (html.scrollHeight || body.scrollHeight) - this.innerHeight,
scrollTop = html.scrollTop || body.scrollTop || 0;
elem.style.opacity = 1 - 1 / scrollHeight * scrollTop;
});
})();
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