diff --git a/www/assert/main.js b/www/assert/main.js
index 0913674ae..ad7883de3 100644
--- a/www/assert/main.js
+++ b/www/assert/main.js
@@ -7,7 +7,8 @@ define([
     '/drive/tests.js',
     '/common/test.js',
     '/common/common-thumbnail.js',
-], function ($, Hyperjson, TextPatcher, Sortify, Cryptpad, Drive, Test, Thumb) {
+    '/common/flat-dom.js',
+], function ($, Hyperjson, TextPatcher, Sortify, Cryptpad, Drive, Test, Thumb, Flat) {
     window.Hyperjson = Hyperjson;
     window.TextPatcher = TextPatcher;
     window.Sortify = Sortify;
@@ -241,6 +242,7 @@ define([
         return cb(true);
     }, "version 2 hash failed to parse correctly");
 
+/*
     assert(function (cb) {
         var getBlob = function (url, cb) {
             var xhr = new XMLHttpRequest();
@@ -266,9 +268,21 @@ define([
             });
         });
     });
+*/
 
     Drive.test(assert);
 
+    assert(function (cb) {
+        // extract dom elements into a flattened JSON representation
+        var flat = Flat.fromDOM(document.body);
+        // recreate a _mostly_ equivalent DOM
+        var dom = Flat.toDOM(flat);
+        // assume we don't care about comments
+        var bodyText = document.body.outerHTML.replace(/<!\-\-[\s\S]*?\-\->/g, '')
+        // check for equality
+        cb(dom.outerHTML === bodyText);
+    });
+
     var swap = function (str, dict) {
         return str.replace(/\{\{(.*?)\}\}/g, function (all, key) {
             return typeof dict[key] !== 'undefined'? dict[key] : all;
diff --git a/www/common/flat-dom.js b/www/common/flat-dom.js
index c6b2bc4d9..51c3d07b3 100644
--- a/www/common/flat-dom.js
+++ b/www/common/flat-dom.js
@@ -17,6 +17,7 @@ define([], function () {
         return data;
     };
 
+    var identity = function (x) { return x; };
     Flat.fromDOM = function (dom) {
         var data = {
             map: {},
@@ -26,18 +27,20 @@ define([], function () {
         var uid = function () { return i++; };
 
         var process = function (el) {
-            if (!el || el.attributes) { return void console.error(el); }
-            var id = uid();
+            var id;
             if (!el.tagName && el.nodeType === Node.TEXT_NODE) {
+                id = uid();
                 data.map[id] = el.textContent;
                 return id;
             }
+            if (!el || !el.attributes) { return void console.error(el); }
+            id = uid();
             data.map[id] = [
                 el.tagName,
                 getAttrs(el),
                 slice(el.childNodes).map(function (e) {
                     return process(e);
-                })
+                }).filter(identity)
             ];
             return id;
         };
@@ -49,6 +52,7 @@ define([], function () {
     Flat.toDOM = function (data) {
         var visited = {};
         var process = function (key) {
+            if (!key) { return; } // ignore falsey keys
             if (visited[key]) {
                 // TODO handle this more gracefully.
                 throw new Error('duplicate id or loop detected');