Coding a Navigation Menu Bar with drop down subpages

Over the past days, I was thinking how to design a navigation menu bar that when you hover it, the sub pages will be shown. I know it’s sounds so easy but the challenging part are these:

  • CSSing the Navigation Bar
  • Designing the Database since will be implementing a sub page that has a sub page and so on and so forth(unlimited SUBs)…
  • Coding the design in PHP and HTML

So then, after days of combat I made my own. Thanks also to my thorough research.

I created 3 files. A class for calling the categories, the HTML and the CSS.

Here’s my Code:

HTML

<?php
     require_once 'categories.php';
     $cat = new Categories();
     $menu = $cat->get_menu();
?>
 <div id="access">
    <div id="nav">
      <div class="menu-header"><?= $menu; ?></div>
     </div>
 </div>

Categories.php (Click here for more info about this class)

<?php
class Categories
{
	var $exclude;
	var $depth;

	function __construct() {
		$this->exclude = array();
		$this->depth = 1;
	}

	function get_menu()
	{
		$nav_query = mysql_query("SELECT * FROM `categories` ORDER BY 'category_id'") or die( mysql_error() );

		$tree = "<ul class='menu'>";					// Clear the directory tree
		$this->depth = 1;					// Child level depth.
		$top_level_on = 1;			// What top-level category are we on?
		array_push($this->exclude, 0);	// Put a starting value in it

		while ( $nav_row = mysql_fetch_array( $nav_query ) )
		{
			$goOn = 1; // Resets variable to allow us to continue building out the tree.
			for( $x = 0; $x < count( $this->exclude ); $x++ )// Check to see if the new item has been used
			{
				if ( $this->exclude[$x] == $nav_row['category_id'] )
				{
					$goOn = 0;
					break; // Stop looking b/c we already found that it's in the exclusion list and we can't continue to process this node
				}
			}
			if ( $goOn == 1 )
			{
				#top category or in other words category who's parent_id is 0
				$tree .= "<li class='menu-item'><a href='#'>".$nav_row['name']."</a>"; // Process the main tree node
				array_push( $this->exclude, $nav_row['category_id'] ); // Add to the exclusion list

				if ( $nav_row['category_id'] < 6 )
				{ $top_level_on = $nav_row['category_id']; }

				$tree .= $this->build_child( $nav_row['category_id'] ); // Start the recursive function of building the child tree
				$tree .= "</li>";
			}
		}

		return $tree."</ul>";
		// echo "</ul>";
	}

	function build_child( $oldID )// Recursive function to get all of the children...unlimited depth
	{
		$child_query = mysql_query( "SELECT * FROM `categories` WHERE parent_id=" . $oldID ) or die( mysql_error() );
		$tempTree .= "<ul class='sub-menu'>";
		while ( $child = mysql_fetch_array( $child_query ) )
		{
			if ( $child['category_id'] != $child['parent_id'] )
			{
				$tempTree .= "<li class='menu-item'><a href='#'>" . $child['name'] . "</a>";
				$this->depth++;		// Incriment depth b/c we're building this child's child tree  (complicated yet???)
				$tempTree .= $this->build_child( $child['category_id'] ); // Add to the temporary local tree
				$this->depth--;		// Decrement depth b/c we're done building the child's child tree.
				array_push( $this->exclude, $child['category_id'] );			// Add the item to the exclusion list
			}
		}
		$tempTree .= "</li></ul>";
		return $tempTree;		// Return the entire child tree
	}

}
?>

CSS

#access {
	display: block;
	float: left;
	height: 31px;
	margin: 0 auto;
	width: 1000px;
}
#access .menu-header, div.menu {
	font-size: 13px;
	margin-left: 12px;
	width: 1000px;
}
#access .menu-header ul, div.menu ul {
	list-style: none outside none;
	margin: 0;
}
#access ul ul {
	box-shadow: 0 3px 3px rgba(0, 0, 0, 0.2);
	display: none;
	float: left;
	left: 0;
	position: absolute;
	top: 38px;
	width: 180px;
	z-index: 99999;
}
#access ul ul ul {
	left: 100%;
	top: 0;
}
#access .menu-header li, div.menu li {
	float: left;
	position: relative;
}
#access ul ul li {
	min-width: 180px;
}
#access li:hover > a, #access ul ul *:hover > a {
	background: none repeat scroll 0 0 #333333;
	color: #FFFFFF;
}

#access ul li:hover > ul{
	display: block;
}
#access ul ul a {
	background: none repeat scroll 0 0 #333333;
	height: auto;
	line-height: 1em;
	padding: 10px;
	width: 160px;
}
#access a {
	display: block;
	line-height: 34px;
	padding: 0 10px;
	text-decoration: none;
}

Now everything is just a piece of cake! Since this code is designed to be dynamic, there’s no worrying how many sub pages you’ll create.
The finish product would look like this:

Just edit the CSS and you’ll be golden!
Hope this help someone! Have a Happy Coding! :)

2 thoughts on “Coding a Navigation Menu Bar with drop down subpages

  1. Hmm, If you try to trace the code, you’ll have an idea where to put the “Adding of URL on the last child”.

    Just a hint:You can process that one on the build_child() function.

    Hope that helps!

    Thanks! :)

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