add class while scrolling

by secretgspot

HTML

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CSS

.scrolling {
    background: #eee;
}

JavaScript

$(function() {

    var timer, el = $('body'),
        flag = false;
    $(window).scroll(function() {
        if (!flag) {
            flag = true;
            el.addClass('scrolling');
        }
        clearTimeout(timer);
        timer = setTimeout(function() {
            el.removeClass('scrolling');
            flag = false;
        }, 200);
    });

});