Is this a CSS or jQuery problem?

Is this a CSS or jQuery problem?

This shouldn't be a problem with the jQuery but the CSS, but i just can't see what im doing wrong.

Have adapted a jQuery tabbed menu system for my own site, here's a snippet:

$(document).ready(function(){ 
    $("#nav > li").click(function(e){ 
        switch(e.target.id){ 
            case "html": 
                //change status & style menu
                $("#html").addClass("active"); 
                $("#css").removeClass("active"); 
                $("#js").removeClass("active");
                $("#php").removeClass("active");
                //display selected division, hide others 
                $("div.html").slideDown(); 
                $("div.css").css("display", "none"); 
                $("div.js").css("display", "none");
                $("div.php").css("display", "none");
            break;


so it adds the 'active' class to the tab that is clicked. it's not hosted yet so i can't give you a link.

the css for active is just
.active
{
background : #6699ff;
}


when i have anchors between the <li>'s and style the anchors instead, it works (well i can set 'color') but not when i take them out (i dont need them).

so because it's styling links i am assuming it is a css problem rather than a jquery.

any help appreciated

thanks[/code]