Does Firefox support position: relative on table elements?

Question

Easy and most proper way would be to wrap the contents of the cell in a div and add position:relative to that div.

example:

<td>
  <div style="position:relative">
      This will be positioned normally
      <div style="position:absolute; top:5px; left:5px;">
           This will be positioned at 5,5 relative to the cell
      </div>
  </div>
</td>

That should be no problem. Remember to also set:

display: block;

Since every web browser including Internet Explorer 7, 8 and 9 correctly handle position:relative on a table-display element and only FireFox handles this incorrectly, your best bet is to use a JavaScript shim. You shouldn't have to rearrange your DOM just for one faulty browser. People use JavaScript shims all the time when IE gets something wrong and all the other browsers get it right.

Here is a completely annotated jsfiddle with all the HTML, CSS, and JavaScript explained.

http://jsfiddle.net/mrbinky3000/MfWuV/33/

My jsfiddle example above uses "Responsive Web Design" techniques just to show that it will work with a responsive layout. However, your code doesn't have to be responsive.

Here is the JavaScript below, but it won't make that much sense out of context. Please check out the jsfiddle link above.

$(function() {
    // FireFox Shim
    // FireFox is the *only* browser that doesn't support position:relative for
    // block elements with display set to "table-cell." Use javascript to add
    // an inner div to that block and set the width and height via script.
    if ($.browser.mozilla) {

        // wrap the insides of the "table cell"            
        $('#test').wrapInner('<div class="ffpad"></div>');

        function ffpad() {
            var $ffpad = $('.ffpad'),
                $parent = $('.ffpad').parent(),
                w, h;

            // remove any height that we gave ffpad so the browser can adjust size naturally.
            $ffpad.height(0);

            // Only do stuff if the immediate parent has a display of "table-cell".  We do this to
            // play nicely with responsive design.
            if ($parent.css('display') == 'table-cell') {               

                // include any padding, border, margin of the parent
                h = $parent.outerHeight();

                // set the height of our ffpad div
                $ffpad.height(h);

            }

        }


        // be nice to fluid / responsive designs   
        $(window).on('resize', function() {
            ffpad();
        });

        // called only on first page load
        ffpad();

    }

});

Starting with Firefox 30, you'll be able use position on table components. You can try for yourself with the current nightly build (works as standalone): http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/

Test case (http://jsfiddle.net/acbabis/hpWZk/):

<table>
    <tbody>
        <tr>
            <td style="width: 100px; height: 100px; background-color: red; position: relative">
                <div style="width: 10px; height: 10px; background-color: green; position: absolute; top: 10px; right: 10px"></div>
            </td>
        </tr>
    </tbody>
<table>

You can continue to follow the developers' discussion of the changes here (the topic is 13 years old): https://bugzilla.mozilla.org/show_bug.cgi?id=63895

Judging by recent release history, this could be available as soon as May 2014. I can barely contain my excitement!

EDIT (6/10/14): Firefox 30 was released today. Soon, table positioning won't be an issue in major desktop browsers

As of Firefox 3.6.13, position: relative/absolute do not seem to work on table elements. This seems to be long standing Firefox behaviour. See the following: http://csscreator.com/node/31771

The CSS Creator link posts the following W3C reference:

The effect of 'position:relative' on table-row-group, table-header-group, table-footer-group, table-row, table-column-group, table-column, table-cell, and table-caption elements is undefined. http://www.w3.org/TR/CSS21/visuren.html#positioning-scheme

Try using display:inline-block it worked for me in Firefox 11 giving me positioning capability within the td/th without destroying the layout of the table. That in conjunction with position:relative on a td/th ought to make things work. Just got it working myself.

I had a table-cell element (which was actually a DIV not a TD)

I replaced

display: table-cell;
position: relative;
left: .5em

(which worked in Chrome) with

display: table-cell;
padding-left: .5em

Of course padding usually is added to width in the box model - but tables always seem to have a mind of their own when it comes to absolute widths - so this will work for some cases.