Defer image load

gistfile1.js

var load = function (img) {
    var src = img.getAttribute('data-src');
    if (src && img.src !== src) {
        img.src = src;
    }
};

var find = function () {
    return document.querySelectorAll('.js-defer');
};

var loadAll = function () {
    var items = find();
    var i = items.length;
    while (i--) {
        load(items[i]);
    }
};

var bind = function (src, type, fn) {
    src.addEventListener(type, fn, false);
};

var handleLoad = function () {
    setTimeout(loadAll, 1000);
};

bind(window, 'load', handleLoad);