shortcode plugin javascript doesnt work

Hello, im making a shortcode plugin that adds some tables with some data. I want to be able to hide/show the tables easily, so i print this in the shortcode function. The problem is, the javascript that should be executed by the href=”javascript: switchVisibility(competition87);” is not! Anybody knows what am i doing wrong?

<script type="text/javascript">
function switchVisibility(obj)
{
  if (obj.style.display == "none")
    obj.style.display = "";
  else
    obj.style.display = "none";
}</script>
  <a href="javascript: switchVisibility(competition87);">test</a>
  <div id="competition87" style="display:none;">
    some contents
  </div>
...

ps: the above code is from a post in which ive writen the shortcode