Live Javascript

I was wondering if there is anyway I could use javascrip in a member legend so that when you hover over the word admin on the legend it would make admins bold, I would be able to make it happen if say you clicked the word, but is there anyway you can make it live, so that when you hover over the world they become bold, I would think you would need to assign CSS styles to each group and make some sort of on hover that value = bold but I don't know how to do that so help is appreciated.

<style>
a{color:#000;text-decoration:none;}
a:hover{font-weight:bold;color:#000;}
</style>

<fieldset><legend><a href="#">Admin</a></legend>
Foo Bar
</fieldset>

I kinda meant a member legend on a forum so say for example it was like this -

USers online - An Admin, A mod, Normal Member, Normal Member.

Legend: Admin | Mods | Members.

Say you hovered your mouse over Admin the name of the admins online would become bold.