Toggling <div> Visibility in a Rails App

I'm embarrassed to say that I have not used Javascript in quite a while, but now have to re-familiarize myself with it as I'm learning Ruby and Rails concurrently. :o

Anyway, here's the code I'm working with:

In application.js:

function toggle_visible(obj) {
var el = document.getElementById(obj);
if ( el.style.display != 'none' ) {
el.style.display = 'none';
}
else {
el.style.display = '';
}
}

In the view:
<div id="short_desc_<%= job.id %>">
<%= truncate(job.description, 200) %>
</div>
<div id="long_desc_<%= job.id %>" style="display:none;">
<%= job.description %>
</div>
<%= link_to_function("Expand", "toggle_visible()") %>

This generates an error in Firebug: "el has no properties - toggle_visible(undefined)"

What is it I'm supposed to pass in this situation (since I'm changing the state of two divs)?

Any help is greatly appreciated.

I don't know anything about ruby(?), but if the following line is producing your onclick handler call,
<%= link_to_function("Expand", "toggle_visible()") %> then you may pass some value in the call to match the definition function toggle_visible(obj){
var el = document.getElementById(obj);

A co-worker provided this solution using Prototype (a javascript framework):


<td colspan="3">
<div id="short_desc_<%= job.id %>">
<%= truncate(job.description, 200) %>
<br />
<%= link_to_function("Expand", "$(this).up('td').childElements().invoke('toggle')") %>
</div>
<div id="long_desc_<%= job.id %>" style="display:none;">
<%= job.description %>
<br />
<%= link_to_function("Collapse", "$(this).up('td').childElements().invoke('toggle')") %>
</div>
</td>


Since it only occurs in this file, it was decided to make it an inline call, rather than include it in the .js file that gets included/loaded with all the pages.