Expand/Collapse feature not working in IE7, Firefox 3 OSX, Firefox Windows

I am experimenting an expand/collapse feature which works on most browsers but IE7, FF 3 OSX/Win.

You can see the expand/collapse feature on one of the titles (What We’re Reading: Obama names new envoy to Sudan) in this blog: http://www.one.org/blog/.

Here's the code on the head section:

    <script language="JavaScript" type="text/javascript"><!--

function expand(param) {
 jQuery("div"+param).stop().slideToggle("slow", function() {
    linkname = jQuery("a"+param).html();
    if( jQuery("div"+param).is(":visible") ) {
      jQuery("a"+param).html(expand_text+" "+linkname.substring(collapse_text_length));
    }
    else {
        jQuery("a"+param).html(collapse_text+" "+linkname.substring(expand_text_length));
    }
  });

}
function expander_hide(param) {
        jQuery("div"+param).hide();
        linkname = jQuery("a"+param).html();
        collapse_text  = "▼ Show More";
        expand_text    = "▲ Show Less";
        collapse_text_length = jQuery("<span />").html(collapse_text).text().length;
        expand_text_length = jQuery("<span />").html(collapse_text).text().length;
        jQuery("a"+param).html(collapse_text + " " + linkname);
        jQuery("a"+param).show();
}
//--></script>

The code inside the body text of the blog is:

    <a style="display:none;" id="te753358020" href="javascript:expand('#te753358020')"> </a>

<div class="te_div" id="te753358020"><script language="JavaScript" type="text/javascript">expander_hide('#te753358020');</script><a href="http://www.nytimes.com/2011/04/02/world/africa/02ivory.html?_r=1&amp;ref=afr开发者_开发问答ica"><br />

When I try to click the Show More link, it doesn't respond. The text that should be hidden is also displayed in IE7.

What would be the work-around for this?

Thanks,

---

I suggest opening the page in IE7, add some debug messages to see on which line of expander_hide it fails on.