[рони]

Nlk,

function throttle(fn, wait) {
        var time = Date.now();
        return function() {
            if ((time + wait - Date.now()) < 0) {
                fn();
                time = Date.now();
            }
        }
    }
    var fade = throttle(showFadeElem, 300);
    document.addEventListener("scroll", fade, false);


    document.removeEventListener("scroll", fade, false);