1 files changed, 10 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..ceaa2721d7
--- /dev/null
+++ b/browser/base/content/test/general/browser_duplicateIDs.js
@@ -0,0 +1,10 @@
+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;
+  });
+}