Can't Get jquery.matchHeight to Work

Can't Get jquery.matchHeight to Work

I'm trying to match the height of the content area and sidebar on the following site:

I've added the following line of code to my file js.js
  1. $('.height-page').matchHeight();

Here is the class for my content area:
  1. <div id="content" class="grid_8 height-page">

And my sidebar:
  1. <aside id="sidebar" class="grid_4">
  2.     <div class="content height-page">

The script appear to be loading fine, just they're not matching the height. All I get output for both elements is along these lines:
  1. <div class="grid_8 height-page" id="content" style="">

I did originally target each element in the Js with their individual IDs / classes, but couldn't get that to work either. So then I thought maybe I can only apply the height matching to specific classes, hence me going with .height-page , but of course that doesn't work either

Can anyone see what I'm doing wrong?

http://www.mattpealing.co.uk