Javascript - popup window does not display (not even blocked)

[Milan Knizek]

In firefox-3.0beta5 (ubuntu 8.04), the popup window that should be invoked by javascript does not display (nothing happens).

The pages affected are http://www.anonce.cz/ (buy/sell adverts server)

Direct link to one of the adverts:
http://www.annonce.cz/jnp/inzerat/detail/index.html?articleId=2882639&webId=WVJDSS

Click on a green box with text "Kontaktni informace" - a window should popup - it discloses info about contact information for the seller (phone, etc).

In the last stable firefox 2 this page works as expected. I have the pop-up window blocking functionality switched off.

Piece of the source code that could be relevant is here:

<a href="javascript:void(0);" title="Kontaktní informace" class="button large green floatLeft dont-print show-if-prototype anchor-contact">
     <span class="padding">
      <span class="t"><span class="r"><span class="b"><span class="l"><span class="tl"><span class="tr"><span class="br"><span class="bl">
       <span class="content">Kontaktní informace</span></span></span></span></span></span></span></span></span>
     </span>
    </a>
<div id="ad-contact" class="clear hide-if-prototype">
    <h2 class="highlight">Kontaktní informace:</h2>

    <table summary="Kontaktní informace" class="detail">
<tr>
    <th>Telefon:</th>
    <td class="normal">Volám na inzerát z ANNONCE <strong>+420&nbsp;775&nbsp;130&nbsp;075</strong>.</td>
   </tr>
<tr>

   <th>E-mail:</th>
   <td><a href="/jnp/inzerat/detail/odpoved/index.html?articleId=2882639&amp;webId=WVJDSS" title="Napsat e-mail" class="icon- ajax-popup-button apb-config-responseAjaxButton" target="_blank"><email address hidden></a></td>
  </tr>
<tr class="row last">
      <td colspan="2">
       <p class="smaller">Obsah je poskytnut pouze pro soukromé použití! <br />Jakékoliv další šíření je přísně zakázáno!</p>
      </td>

     </tr>
    </table>
   </div>

[Milan Knizek (knizek)]

In Firefox 3.0.3 this error does not appear anymore (Ubuntu Intrepid).