diff --git a/index.html b/index.html
index c468ca7a0..38a17504b 100644
--- a/index.html
+++ b/index.html
@@ -30,6 +30,7 @@
         <script src='js/id/taginfo.js'></script>
         <script src='js/id/renderer/style.js'></script>
         <script src='js/id/renderer/background.js'></script>
+        <script src='js/id/renderer/background_source.js'></script>
         <script src='js/id/renderer/map.js'></script>
         <script src='js/id/renderer/hash.js'></script>
         <script src='js/id/renderer/markers.js'></script>
diff --git a/js/id/renderer/background.js b/js/id/renderer/background.js
index cb5ade511..92d1f2464 100644
--- a/js/id/renderer/background.js
+++ b/js/id/renderer/background.js
@@ -63,39 +63,3 @@ iD.Background = function() {
     return background;
 };
 
-iD.BackgroundSource = {};
-
-// derive the url of a 'quadkey' style tile from a coordinate object
-iD.BackgroundSource.template = function(template, subdomains) {
-    return function(coord) {
-        var u = '';
-        for (var zoom = coord[2]; zoom > 0; zoom--) {
-            var byte = 0;
-            var mask = 1 << (zoom - 1);
-            if ((coord[0] & mask) !== 0) byte++;
-            if ((coord[1] & mask) !== 0) byte += 2;
-            u += byte.toString();
-        }
-        // distribute requests against multiple domains
-        var t = subdomains ?
-            subdomains[coord[2] % subdomains.length] : '';
-        return template
-            .replace('{t}', t)
-            .replace('{u}', u)
-            .replace('{x}', coord[0])
-            .replace('{y}', coord[1])
-            .replace('{z}', coord[2]);
-    };
-};
-
-iD.BackgroundSource.Bing = iD.BackgroundSource.template(
-    'http://ecn.t{t}.tiles.virtualearth.net/tiles/a{u}.jpeg?g=587&mkt=en-gb&n=z',
-    [0, 1, 2, 3]);
-
-iD.BackgroundSource.Tiger2012 = iD.BackgroundSource.template(
-    'http://{t}.tile.openstreetmap.us/tiger2012_roads_expanded/{z}/{x}/{y}.png',
-    ['a', 'b', 'c']);
-
-iD.BackgroundSource.OSM = iD.BackgroundSource.template(
-    'http://{t}.tile.openstreetmap.org/{z}/{x}/{y}.png',
-    ['a', 'b', 'c']);
diff --git a/js/id/renderer/background_source.js b/js/id/renderer/background_source.js
new file mode 100644
index 000000000..8e7f6e019
--- /dev/null
+++ b/js/id/renderer/background_source.js
@@ -0,0 +1,36 @@
+iD.BackgroundSource = {};
+
+// derive the url of a 'quadkey' style tile from a coordinate object
+iD.BackgroundSource.template = function(template, subdomains) {
+    return function(coord) {
+        var u = '';
+        for (var zoom = coord[2]; zoom > 0; zoom--) {
+            var byte = 0;
+            var mask = 1 << (zoom - 1);
+            if ((coord[0] & mask) !== 0) byte++;
+            if ((coord[1] & mask) !== 0) byte += 2;
+            u += byte.toString();
+        }
+        // distribute requests against multiple domains
+        var t = subdomains ?
+            subdomains[coord[2] % subdomains.length] : '';
+        return template
+            .replace('{t}', t)
+            .replace('{u}', u)
+            .replace('{x}', coord[0])
+            .replace('{y}', coord[1])
+            .replace('{z}', coord[2]);
+    };
+};
+
+iD.BackgroundSource.Bing = iD.BackgroundSource.template(
+    'http://ecn.t{t}.tiles.virtualearth.net/tiles/a{u}.jpeg?g=587&mkt=en-gb&n=z',
+    [0, 1, 2, 3]);
+
+iD.BackgroundSource.Tiger2012 = iD.BackgroundSource.template(
+    'http://{t}.tile.openstreetmap.us/tiger2012_roads_expanded/{z}/{x}/{y}.png',
+    ['a', 'b', 'c']);
+
+iD.BackgroundSource.OSM = iD.BackgroundSource.template(
+    'http://{t}.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    ['a', 'b', 'c']);
diff --git a/test/index.html b/test/index.html
index 5f681b444..f5234875f 100644
--- a/test/index.html
+++ b/test/index.html
@@ -33,6 +33,7 @@
     <script src='../js/id/renderer/style.js'></script>
 
     <script src='../js/id/renderer/background.js'></script>
+    <script src='../js/id/renderer/background_source.js'></script>
     <script src='../js/id/renderer/map.js'></script>
     <script src='../js/id/renderer/hash.js'></script>
     <script src='../js/id/renderer/markers.js'></script>