Tryit Editor v2.7

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
    border: 1px solid black;
}
</style>

<script>
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "//hm.baidu.com/hm.js?73c27e26f610eb3c9f3feb0c75b03925";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script>
</head>
<body>

<p><b>Note:</b> The dialog tag is currently only supported in Chrome version 37+, Safari 6+ and Opera 24+.</p>

<table>
  <tr>
    <th>January <dialog open>This is an open dialog window</dialog></th>
    <th>February</th>
    <th>March</th>
  </tr>
  <tr>
    <td>31</td>
    <td>28</td>
    <td>31</td>
  </tr>
</table>

</body>
</html>