Home » Html » Where do tabindex=“0” HTML elements end up in the tabbing order?

Where do tabindex=“0” HTML elements end up in the tabbing order?

Posted by: admin November 29, 2017 Leave a comment

Questions:

In what order are elements with a tabindex value of 0 focused when the web page is tabbed?

Answers:

The HTML specification states:

Elements that have identical tabindex
values should be navigated in the
order they appear in the character
stream.

Questions:
Answers:

tabindex assignments are handled the following way (for elements that support the tabindex attribute):

  • Positive numbers (1,2,3…32767) are handled in tab order.
  • 0 is handled in source order (the order it appears in the DOM)
  • -1 is ignored during tabbing but is focusable.

This information is taken from : http://www.w3.org/TR/html401/interact/forms.html#adef-tabindex

Questions:
Answers:

It’s a bit more complicated than Alan Haggai Alavi’s answer.

After parsing, IE8 and Opera do as the HTML4 spec says. Firefox and Chrome however use DOM order. This matters with malformed markup like this.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
  <head>
    <title>Test case 1</title>
  </head>
  <body>
    <form>
      <table>
        <tr><td><input id="first" value="first in the character stream" tabindex="0"></td></tr>
        <div><input id="second" value="second in the character stream" tabindex="0"></div>
      </table>
    <form>
  </body>
</html>

You might well argue that with malformed mark-up all bets are off anyway, so what about JavaScript?

Consider this case:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
  <head>
    <title>Test case 2</title>
    <script type="text/javascript">
      moveFirst = function()
      {
        var f = document.getElementById("first");
        f.parentNode.removeChild(f);
        document.body.appendChild(f);
      }
    </script>
  </head>
  <body>
    <form>
      <table>
        <tr><td><input id="first" value="first in the character stream" tabindex="0"></td></tr>
        <tr><td><div><input id="second" value="second in the character stream" tabindex="0"></div></td></tr>
      </table>
    <form>
    <div onclick="moveFirst()">move</div>
  </body>
</html>

In this case, when a user clicks on “move”, IE8, Firefox, Chrome and Opera all use DOM order, not character stream order.

Finally HTML5 offers pretty much no guarantees about the tab order between elements that have a tabindex of 0, merely stating that it should follow platform conventions.

Questions:
Answers:

tabindex="0" can include tabbing to non-page elements of the web browser, such as the URL address bar.

Tested to be the case for Firefox 32.03.