1 files changed, 11 insertions, 0 deletions
diff --git a/browser/base/content/test/general/browser_duplicateIDs.js b/browser/base/content/test/general/browser_duplicateIDs.js
new file mode 100644
index 0000000000..b0c65c6af6
--- /dev/null
+++ b/browser/base/content/test/general/browser_duplicateIDs.js
@@ -0,0 +1,11 @@
+function test() {
+  var ids = {};
+  Array.prototype.forEach.call(
+    document.querySelectorAll("[id]"),
+    function (node) {
+      var id = node.id;
+      ok(!(id in ids), id + " should be unique");
+      ids[id] = null;
+    }
+  );
+}