<!DOCTYPE html>
<title>dataset: should return 'undefined' for non-existent properties</title>
<link rel="author" title="Ms2ger" href="mailto:ms2ger@gmail.com">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
var div = document.createElement("div");
test(function() {
  assert_false("foo" in div.dataset);
  assert_equals(div.dataset.foo, undefined);
}, "Should return 'undefined' before setting an attribute")
test(function() {
  div.setAttribute("data-foo", "value");
  assert_true("foo" in div.dataset);
  assert_equals(div.dataset.foo, "value");
}, "Should return 'value' if that's the value")
test(function() {
  div.setAttribute("data-foo", "");
  assert_true("foo" in div.dataset);
  assert_equals(div.dataset.foo, "");
}, "Should return the empty string if that's the value")
test(function() {
  div.removeAttribute("data-foo");
  assert_false("foo" in div.dataset);
  assert_equals(div.dataset.foo, undefined);
}, "Should return 'undefined' after removing an attribute")
</script>