CSS : Drop down menu

he first part of this tutorial is dedicated to the task of building a working CSS-only dropdown menu (also known as suckerfish menu), the second part will show you how you can pimp the whole thing with a few lines of jQuery.

The CSS-only menu is cross browser tested and from what I can tell works with all browsers except for IE6.
The Internet Explorer needs the addition of our jQuery function to work properly.

To create a CSS-only dropdown menu that works without Javascript (even in IE6), you need tons of extra markup and CSS, if you really need this for any reason check out Stu Nicholls CSSplay, he addresses this problem with heavy (ab)use of conditional comments =)

Now that you have a little bit of background information, lets create our own menu:

First of all we need the XHTML Structure of our soon-to-be terrific menu. We will use a nested list for this purpose, top level list id is “nav”:

<ul id="nav">
    <li><a href="#">1 HTML</a></li>
    <li><a href="#">2 CSS</a></li>
    <li><a href="#">3 Javascript</a>
        <ul>
            <li><a href="#">3.1 jQuery</a>
                <ul>
                    <li><a href="#">3.1.1 Download</a></li>
                    <li><a href="#">3.1.2 Tutorial</a></li>
                </ul>
            </li>
            <li><a href="#">3.2 Mootools</a></li>
            <li><a href="#">3.3 Prototype</a></li>
        </ul>
    </li>
</ul>

Thats it for the HTML part; without CSS styling our menu looks like this: Step 1

Now for the stylesheet part:

#nav, #nav ul{
     margin:0;
     padding:0;
     list-style-type:none;
     list-style-position:outside;
     position:relative;
     line-height:1.5em;
 }

This removes the indents browsers tend to make, as well as the bullets from #nav and all its child-ul elements. The “position:relative” is needed since we will arrange some of the contained elements with position:relative and absolute. This is necessary since relative and absolute positioned elements are positioned according to their containing blocks with a position attribute, other then static.

Line-height defines the height of each list item. You could set the height attribute for your list-items to define their height, but line-height will center the link text vertically without the need to play with margins and paddings.

 #nav a:link, #nav a:active, #nav a:visited{
    display:block;
    padding:0px 5px;
    border:1px solid #333;
    color:#fff;
    text-decoration:none;
    background-color:#333;
 }

#nav a:hover{
    background-color:#fff;
    color:#333;
}

This one is pretty straight forward:
it will style each hyper link in our menu a little bit. At this time the menu looks like this:Step 2

Now lets add some more styles:

#nav li{
    float:left;
    position:relative;
}

This will align our list elements horizontally.

#nav ul {
    position:absolute;
    width:12em;
    top:1.5em;
    display:none;
}

This will position the nested Lists right beyond the main menu and give them a width of 12em. The width attribute is needed so that the list items within display vertically again. The Top attribute should have the same value as the line-height attribute we defined for #nav.

#nav li ul a{
    width:12em;
    float:left;
}

This will set the width of the hyper links to 12 em (which in combination with the width of the UL set above results in a horizontally displayed sub menu, despite of the ongoing float:left)

#nav ul ul{
 top:auto;
 }

#nav li ul ul {
    left:12em;
    margin:0px 0 0 10px;
    }

#nav li:hover ul ul, #nav li:hover ul ul ul, #nav li:hover ul ul ul ul{
    display:none;
    }
#nav li:hover ul, #nav li li:hover ul, #nav li li li:hover ul, #nav li li li li:hover ul{
    display:block;
    }

#nav ul ul and #nav li ul ul define where we display the sub menus.

The hover states define which items we want to show when hovering over an item (only the next sub level, not all of them)

After applying these styles we got this menu: Step3

If you are working with a browser other than IE6 you should have a basic dropdown menu now.

Gogo jQuery!

So lets spice up the menu a little bit. First of all here is the whole jQuery Code I used to create the effect:

function mainmenu(){
$(" #nav ul ").css({display: "none"}); // Opera Fix
$(" #nav li").hover(function(){
  $(this).find('ul:first').css({visibility: "visible",display: "none"}).show(400);
  },function(){
  $(this).find('ul:first').css({visibility: "hidden"});
  });
}

 $(document).ready(function(){
 mainmenu();
});

Step by step description:

$(" #nav ul ").css({display: "none"}); // Opera Fix

This is a small fix for Opera, which doesn’t hide the menus fast enough, if you hover above them and so creates a flickering effect. $(” #nav ul “) is the jQuery way to select all unordered lists in #nav. Usage of this is similar to selecting CSS elements. The.css({display:”none”}) sets the display attribute for all Unordered lists to none.

$(" #nav li").hover(function(){ // here goes mouse over effect
                  },function(){ // here goes mouse out effect
                               });

This is the jQuery function for hovering. Really simple to use: first function lets you define what happens when you hover over a specific item( in our case a list item), second function is used for the mouse out event.

$(this).find('ul:first:hidden').css({visibility: "visible",display: "none"}).show(400);

This function finds the first hidden unordered list within the currently hovered list item and shows it. The function “.show” works only under specific circumstances, this is why we set the display to none. The number between the braces defines the animation speed in milliseconds.

$(this).find('ul:first').css({visibility: "hidden"});

This is the mouse out event: we use visibility instead of display since the show function mentioned above, sets display to “block” at the end of the animation. This way if you would hover just a short moment over the item the item would not display for the ongoing animation and then pop out all of a sudden. Using visibility prevents this flickering.

 $(document).ready(function(){
 mainmenu();
});

This function will call our mainmenu() function as soon as the html document is ready.

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