<!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(new TypeError(), function() {
    "use strict";
    delete form[0];
  });
  assert_equals(form[0], old_item);
}, 'Trying to delete an indexed property name should never work');
</script>