1 files changed, 45 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/semantics/forms/the-form-element/form-indexed-element.html b/testing/web-platform/tests/html/semantics/forms/the-form-element/form-indexed-element.html
new file mode 100644
index 0000000000..5ea96d3d1b
--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/forms/the-form-element/form-indexed-element.html
@@ -0,0 +1,45 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>form.elements: indexed</title>
+<link rel="author" title="Ivan.Yang" href="mailto:jsyangwenjie@gmail.com">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<div id="test">
+<form id=form>
+<input type="radio" name="radio1" id="r1" value=1>
+<input type="radio" name="radio2" id="r2" value=2>
+</form>
+</div>
+<script>
+test(function() {
+  var form = document.getElementById("form");
+  assert_equals(form[0], document.getElementById("r1"));
+  assert_equals(form[1], document.getElementById("r2"));
+  assert_equals(form[2], undefined);
+  assert_equals(form[-1], undefined);
+}, "form.elements should be accessed correctly by index")
+
+test(function(){
+  var form = document.getElementById("form");
+  var old_item = form[0];
+  var old_desc = Object.getOwnPropertyDescriptor(form, 0);
+  assert_equals(old_desc.value, old_item);
+  assert_true(old_desc.enumerable);
+  assert_true(old_desc.configurable);
+  assert_false(old_desc.writable);
+
+  Object.prototype[0] = 5;
+  this.add_cleanup(function () { delete Object.prototype[0]; });
+  assert_equals(form[0], old_item);
+
+  delete form[0];
+  assert_equals(form[0], old_item);
+
+  assert_throws_js(TypeError, function() {
+    "use strict";
+    delete form[0];
+  });
+  assert_equals(form[0], old_item);
+}, 'Trying to delete an indexed property name should never work');
+</script>