Vine's embed script

embed.js

! function() {
    function hasClass(el, klass) {
        return el.className.match(new RegExp("(\\s|^)" + klass + "(\\s|$)"))
    }

    function addClass(el, klass) {
        hasClass(el, klass) || (el.className += " " + klass)
    }

    function removeClass(el, klass) {
        if (hasClass(el, klass)) {
            var regex = new RegExp("(\\s|^)" + klass + "(\\s|$)");
            el.className = el.className.replace(regex, " ")
        }
    }
    if (!window.VINE_EMBEDS) {
        window.VINE_EMBEDS = !0, window.setInterval(function() {
            for (var els = document.querySelectorAll('iframe[src*="vine.co"]'), i = 0; i < els.length; i++) {
                var top = els[i].getBoundingClientRect().top;
                top > -300 && top < document.documentElement.clientHeight ? (addClass(els[i], "playing"), els[i].contentWindow.postMessage("play", "*")) : (removeClass(els[i], "playing"), els[i].contentWindow.postMessage("pause", "*"))
            }
        }, 100);
        var d = window.addEventListener ? "addEventListener" : "attachEvent",
            on = window[d],
            messageEvent = "attachEvent" == d ? "onmessage" : "message";
        on(messageEvent, function(el) {
            var e = el.data.split("::");
            var url = e[1].match(/https?:\/\/.+?(\/.+)$/)[1];
            var iframes = iframes = document.querySelectorAll('iframe[src$="' + url + '"]');
            if ("height" == e[0]) {
                for (var i = 0; i < iframes.length; i++) {
                    var h = parseInt(e[2], 10);
                    iframes[i].style.removeProperty ? iframes[i].style.removeProperty("height") : iframes[i].style.removeAttribute("height"), iframes[i].height = 1 * h;
                }
            }
            else if ("unmute" == e[0]) {
                for (var iframe = null, i = 0; i < iframes.length; i++) {
                    iframe = iframes[i];
                    addClass(iframes[i], "unmuted");
                }
                iframes = document.querySelectorAll("iframe.loaded");
                for (var k = 0; k < iframes.length; k++) {
                    if (iframes[k] != iframe) {
                        removeClass(iframes[k], "unmuted");
                        iframes[k].contentWindow.postMessage("mute", "*");
                    }
                }
            }
            else if ("loaded" == e[0]) {
                for (var i = 0; i < iframes.length; i++) {
                    iframes[i].setAttribute("frameborder", 0), addClass(iframes[i], "loaded");
                    iframes[i].contentWindow.postMessage("hasEmbedScript", "*");
                }
            }
        })
    }
}();