webm inline player for so chat

webminline.js

(function() {
    "use strict";

    function parseNode(node) {
        if (node.classList && node.classList.contains('message') && !node.classList.contains('pending')) {
            var content = node.querySelector('.content');
            if ([].filter.call(content.childNodes, function(child) {
                return (child.nodeType === 1 || child.nodeType === 3)
            }).length > 1) return; // shut up
            var link = content.querySelector('a');
            if (!link || !/(webm|gifv)$/.test(link.href)) return;
            var video = document.createElement('video');
            video.controls = true;
            video.src = link.href.replace(/(gifv)$/, 'webm');
            video.width = 320;
            video.height = 240;
            link.parentNode.replaceChild(video, link);
        }
    }
    var chat = document.getElementById('chat');
    [].forEach.call(chat.querySelectorAll('.user-container .message'), parseNode);
    new MutationObserver(function(records) {
        records.forEach(function(record) {
            [].forEach.call(record.addedNodes, parseNode);
        });
    }).observe(chat, {
        childList: true,
        subtree: true
    });
}());