My client wants the sub navigation to appear when the main navigation is hovered (sub pages then appear).

This works fine in IE and Opera (see http://thepritchardgroup.net/ ) however in FireFox nothing happens.

Any help?

Related CSS:
Code:
.hidden {
display: none;
}
Related HTML:
Code:
	<ul id="nav">
		<li<?php if(is_page('2')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=2" title="About Us" onmouseover="subnav2.style.display = 'block'; subnav3.style.display = 'none';  subnav4.style.display = 'none';  subnav5.style.display = 'none';  subnav7.style.display = 'none'; ">About Us</a></li>
		<li<?php if(is_page('3')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=3" title="Expertise" onmouseover="subnav3.style.display = 'block'; subnav2.style.display = 'none';  subnav4.style.display = 'none';  subnav5.style.display = 'none';  subnav7.style.display = 'none'; ">Expertise</a></li>
		<li<?php if(is_page('4')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=4" title="Clients" onmouseover="subnav4.style.display = 'block'; subnav3.style.display = 'none';  subnav2.style.display = 'none';  subnav5.style.display = 'none';  subnav7.style.display = 'none'; ">Clients</a></li>
		<li<?php if(is_page('5')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=5" title="Contact Us" onmouseover="subnav5.style.display = 'block'; subnav3.style.display = 'none';  subnav4.style.display = 'none';  subnav2.style.display = 'none';  subnav7.style.display = 'none'; ">Contact Us</a></li>
		<li<?php if(is_page('6')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=6" title="Site Map" onmouseover="subnav2.style.display = 'none'; subnav3.style.display = 'none';  subnav4.style.display = 'none';  subnav5.style.display = 'none';  subnav7.style.display = 'none'; ">Site Map</a></li>
		<li<?php if(is_page('7')) { ?> class="current_page_item"<?php } ?>><a href="<?php bloginfo('url'); ?>/?page_id=7" title="Disclaimer" onmouseover="subnav7.style.display = 'block'; subnav3.style.display = 'none';  subnav4.style.display = 'none';  subnav5.style.display = 'none';  subnav2.style.display = 'none'; ">Disclaimer</a></li>
	</ul>

AND

	<div id="sub-nav-wrap">
	
	<ul id="subnav2"<?php if(!is_page('2')) { echo ' class="hidden"'; } ?>>
		<?php wp_list_pages("title_li=&child_of=2&sort_column=menu_order&show_date=modified&date_format=$date_format&depth=-1"); ?>
	</ul>

	<ul id="subnav3"<?php if(!is_page('3')) { echo ' class="hidden"'; } ?>>
		<?php wp_list_pages("title_li=&child_of=3&sort_column=menu_order&show_date=modified&date_format=$date_format&depth=-1"); ?>
	</ul>

	<ul id="subnav4"<?php if(!is_page('4')) { echo ' class="hidden"'; } ?>>
		<?php wp_list_pages("title_li=&child_of=4&sort_column=menu_order&show_date=modified&date_format=$date_format&depth=-1"); ?>
	</ul>
	
	<ul id="subnav5"<?php if(!is_page('5')) { echo ' class="hidden"'; } ?>>
		<?php wp_list_pages("title_li=&child_of=5&sort_column=menu_order&show_date=modified&date_format=$date_format&depth=-1"); ?>
	</ul>
	
	<ul id="subnav7"<?php if(!is_page('7')) { echo ' class="hidden"'; } ?>>
		<?php wp_list_pages("title_li=&child_of=7&sort_column=menu_order&show_date=modified&date_format=$date_format&depth=-1"); ?>
	</ul>
I will be really grateful if you could help and would throw some money your way (if the mods allow it, that may make it classed at hiring).

Thanks, Andy