Firefox not recognizing link

Firefox is screwing up or I have screwed up. hmmmmm?

[humpg]

I have a submenu that when you click on it a layer appears making it like a dropdown menu. There are a total of 4 buttons in Firefox the first 3 are not even recognized as a link, but the fourth one is when you click on it the submenu appears.

Here is the HTML for all four menu buttons:

1:<a href="#" onclick="toggleSub('sub_product_mth'); return false" onmouseover="MM_showHideLayers('flyout_math1','','hide','hideflyout_sub','','hide')">
<img src="images/ed_layout/prod_menu_btns/str_menu_math.gif" alt="Math Series" border="0" />
</a>

2:<a href="#" onclick="toggleSub('sub_product_hlth'); return false" onmouseover="MM_showHideLayers('flyout_math1','','hide','flyout_math2','','hide','hideflyout_sub','','hide')">
<img src="images/ed_layout/prod_menu_btns/str_menu_hlth.gif" alt="Health Series" border="0" />
</a>

3:<a href="#" onclick="toggleSub('sub_product_lang'); return false" onmouseover="MM_showHideLayers('flyout_hlth2','','hide','flyout_hlth3','','hide','hideflyout_sub','','hide')">
<img src="images/ed_layout/prod_menu_btns/str_menu_lang.gif" alt="Language Series" border="0" />
</a>

4:<a href="#" onclick="toggleSub('sub_product_test'); return false" onmouseover="MM_showHideLayers('flyout_hlth2','','hide','flyout_hlth3','','hide','flyout_lang2','','hide','hideflyout_sub','','hide')">
<img src="images/ed_layout/prod_menu_btns/str_menu_test.gif" alt="Testing Series" width="173" height="41" border="0" />
</a>

And here is the Javascript to toggle submenu on and off:

function toggleSub(submenu) {
if (document.getElementById(submenu).style.display == 'block') {
document.getElementById(submenu).style.display = 'none'
} else {
document.getElementById(submenu).style.display = 'block'
}
}

[BonRouge]

Hmmm... my money's on Firefox being OK.

I think I might be able to help, but I'd need to see more code. Could you send me a link to this in a message? (as posting links is not allowed)