/*! echo-js v1.7.3 | (c) 2016 @toddmotto | https://github.com/toddmotto/echo */
!function (t, e) {
"function" == typeof define && define.amd ? define(function () {
return e(t)
}) : "object" == typeof exports ? module.exports = e : t.echo = e(t)
}(this, function (t) {
"use strict";
var e, n, o, r, c, a = {}, u = function () {
}, d = function (t) {
return null === t.offsetParent
}, i = function (t, e) {
if (d(t))return !1;
var n = t.getBoundingClientRect();
return n.right >= e.l && n.bottom >= e.t && n.left <= e.r && n.top <= e.b
}, l = function () {
(r || !n) && (clearTimeout(n), n = setTimeout(function () {
a.render(), n = null
}, o))
};
return a.init = function (n) {
n = n || {};
var d = n.offset || 0, i = n.offsetVertical || d, f = n.offsetHorizontal || d, s = function (t, e) {
return parseInt(t || e, 10)
};
e = {
t: s(n.offsetTop, i),
b: s(n.offsetBottom, i),
l: s(n.offsetLeft, f),
r: s(n.offsetRight, f)
}, o = s(n.throttle, 250), r = n.debounce !== !1, c = !!n.unload, u = n.callback || u, a.render(), document.addEventListener ? (t.addEventListener("scroll", l, !1), t.addEventListener("load", l, !1)) : (t.attachEvent("onscroll", l), t.attachEvent("onload", l))
}, a.render = function () {
for (var n, o, r = document.querySelectorAll("img[data-echo], [data-echo-background]"), d = r.length, l = {
l: 0 - e.l,
t: 0 - e.t,
b: (t.innerHeight || document.documentElement.clientHeight) + e.b,
r: (t.innerWidth || document.documentElement.clientWidth) + e.r
}, f = 0; d > f; f++)o = r[f], i(o, l) ? (c && o.setAttribute("data-echo-placeholder", o.src), null !== o.getAttribute("data-echo-background") ? o.style.backgroundImage = "url(" + o.getAttribute("data-echo-background") + ")" : o.src = o.getAttribute("data-echo"), c || (o.removeAttribute("data-echo"), o.removeAttribute("data-echo-background")), u(o, "load")) : c && (n = o.getAttribute("data-echo-placeholder")) && (null !== o.getAttribute("data-echo-background") ? o.style.backgroundImage = "url(" + n + ")" : o.src = n, o.removeAttribute("data-echo-placeholder"), u(o, "unload"));
d || a.detach()
}, a.detach = function () {
document.removeEventListener ? t.removeEventListener("scroll", l) : t.detachEvent("onscroll", l), clearTimeout(n)
}, a
});