Dropdown Menu - Make the <ul> submenu 100% width

Question

I am going a bit crazy trying to achieve something my client wants. I could tell them it's not possible but I love a good challenge ;)

Basically, I'm trying to do a dropdown menu in which the dropdown <ul>, or:

ul.menu li ul

is surrounded by a div. Kind of:

<ul class="menu">
   <li>
       <a href="#">Item</a>
       <div class="submenu">
           <ul>.....</ul>
       </div>
   </li>
</ul>

I want that div to have width:100% and fill the whole width of the page but have the UL inside aligned to the appropriate <li>.

The problem is the <div class="submenu"> will be as wide as the relative container, be it the main <ul class="menu"> or a <div> wrapping the <ul class="menu">.

The website itself has 1000px width and is centered width margin:0 auto;

I hope I have explained myself properly :S Here is a link to a mock up I have put together: Dropdown Menu Mock up

Any help highly appreciated.

Thanks, Alex

Answer 1

Old question, but hopefully answer will help someone. I had to work on something similar to this a month or so ago.

Here is a fiddle of what I basically did (note: you have to do some extra work for this to work the same in older IEs): http://jsfiddle.net/doubleswirve/xbLrW/2/

I didn't use a nested div and instead stuck with nested lists. With a basic markup like the following:

<div class="nav">
  <ul>

    <li>
      <a href="#">Products</a>
      <ul>
        <li><a href="#">Widget A</a></li>
        <li><a href="#">Widget B</a></li>
        <li><a href="#">Widget C</a></li>
      </ul>
    </li>

    <li>
      <a href="#">Locations</a>
      <ul>
        <li><a href="#">Location A</a></li>
        <li><a href="#">Location B</a></li>
        <li><a href="#">Location C</a></li>
      </ul>
    </li>

    <li>
      <a href="#">Staff</a>
      <ul>
        <li><a href="#">President</a></li>
        <li><a href="#">VP</a></li>
        <li><a href="#">Manager</a></li>
      </ul>
    </li>

  </ul>
</div>

You can use the following styling:

/* GENERAL */

body { overflow-x: hidden; } /* trick from css-tricks comments */

/* FIRST LEVEL */

.nav > ul > li { 
  display: inline-block; 
  position: relative; 
  padding: 3px 10px 3px 0;
  z-index: 100;
}

/* SECOND LEVEL */

.nav > ul > li > ul {
  position: absolute;
  left: 0;
  top: 100%;
  padding: 0 1000em; /* trick from css-tricks comments */
  margin: 0 -1000em; /* trick from css-tricks comments */
  z-index: 101;
  visibility: hidden;
  opacity: 0;
  background: rgba(255, 240, 240, 0.8);
}

.nav > ul > li:hover > ul {
  visibility: visible;
  opacity: 1;
}

.nav > ul > li > ul > li {
  padding: 3px 0;
}

If you wanted to get snazzy with the CSS, you could add this to the second level ul:

.nav > ul > li > ul {
  ...
  -webkit-transition: all 0.3s ease;
  -moz-transition: all 0.3s ease;
  -o-transition: all 0.3s ease;
  transition: all 0.3s ease;
}

If anyone is interested in making this work similarly in old IEs or wants deeper nested lists, let me know.

To give you a head start, here are some useful links that helped me:

• Full browser width bars (CSS tricks article/comment)
• Fixing z-index (helpful for IE7)

Chris Coyier really covers us at work lol.