Wordpress jquery

Hi all

I have a super simple WP site here as a demo

http://www.ttmt.org.uk/forum/wordpress

It's a header.php, footer.php, index.php and page.php.

I have one page called Page that uses page.php as it's template. The header list the pages so has 'Page' in the header.

Page.php simple has <h4 id="oneBtn">Red</h4>

In header.php I have this jquery to change the color of #oneBtn when the button in the header in clicked.


Code:
<script type="text/javascript">
    
    $(document).ready(function(){
    	$('#nav li a').click(function(){
		$('#oneBtn').css('color','red');
	});
    });  

  </script>
This doesn't work and I can't see why.

Once the page has loaded and the Page button in the header is clicked again