Let Daryl help you help your users. In this article, Daryl provides PHP code to help your users to navigate through your website and knowing exactly where they are at all times. Read more ...
One of the simplest but most important Web interface necessities is always letting the user know where he or she is within your site. This is most often done using visual cues such as highlighted navigation items, which often match the rollover states of the navigation items.
While many content management systems and application frameworks have this sort of functionality built in, these code bases are overkill for simple sites. You don't need Broadvision or Vignette or even any of the Nuke permutations for a 5-10 page brochure site.
Arguably, maintaining such a brochure site requires little enough effort that a templating system isn't even necessary, but I always find it preferable to have one set of templates to maintain. Setting your site up in this manner ensures consistency across pages, and consistency is as important for a small site as for a gargantuan portal (and maybe moreso).
Let's start with some assumptions for our first example. We're working on a 5-page Web site containing pages for home, about, contact, products, and services. All files for the purposes of this example are in the document root directory, and they all share the basic site template. In the navigation, whenever you mouse over any of the five navigation items, the rollover graphic changes colors.
What we wish to accomplish is having the appropriate navigation item for each page highlight automatically when a visitor loads the page. Since this is simplified templating, we've got a top.php, a bottom.php, and a file containing content for each of the five pages. The top and bottom templates contain all the graphical elements and tables that form the design of the site. And each of the content pages encloses its content with php tags to include top.php and bottom.php.
I'm also making the assumption that for each navigation item, if the default image name is "image.jpg," the rollover state image name will be "image1.jpg."
At the top of top.php, you'll want to include the following block, substituting your page names and domain:
<?php
$root="http://www.yourdomain.com";
$server_path="/full/path/to/document_root";
$path=split("/",$_SERVER["REQUEST_URI"]);
$path=array_reverse($path);
if(eregi("index.php",$path[0]) || $path[0]=="")
{
$home=1;
}
elseif(eregi("about.php",$path[0]))
{
$about=1;
}
elseif(eregi("contact.php",$path[0]))
{
$contact=1;
}
elseif(eregi("products.php",$path[0]))
{
$products=1;
}
elseif(eregi("services.php",$path[0]))
{
$services=1;
}
?>
We're taking the request URI and splitting on / in order to get the components of the URL. Then we reverse the components so that we can crawl the array from left to right (or 0 to n if you prefer to think of it that way) and determine what page has been requested.
The first array element represents the page requested, and subsequent elements represent any subdirectories, the domain, and some extra junk that we'll never need. Since we're assuming all files are in the document root, this reversal isn't so important, but once we look at descending into directories, reversing the array just makes the process a little easier.
We could use PHP's parse_url() function here, but if we were descending into directories, we'd then have to split and parse the path element manually anyway, so I just manually parse the URL to start with.
Once we've got our URL parsed, we process the components by going into an if block and performing the eregi() function for each of our possible page names. I use eregi() because my first use of this little tool was for a site that sometimes had query strings to parse. If we use eregi() rather than the == operator, query strings don't necessarily affect our results -- we're looking for a minimum of the passed string in the URL component.
In other words, to eregi(), "contact.php" and "contact.php?subject=Advertising" both evaluate to true. You do have to be careful about naming pages when using this script, however. For example, if you had a page named "sales_contact.php" and another named "press_contact.php," both would evaluate to true in the third elseif above and thus both would have the $contact variable set to 1.
If you want the same nav to be highlighted for both, this is a bonus. If you want different nav to be highlighted for each, you'll need to make sure you pass "sales_contact.php" and "press_contact.php" to the if block separately and set separate variables for each page.
What we're doing in the code chunk above is setting a bunch of flags. Now we have to use those to affect the navigation. I tend to use DreamWeaver's rollover functions to do my navigation, so the code sample displayed below -- a table row containing my nav -- makes use of those functions. Obviously, you can modify this to suit your needs. The principle behind the navigation swap will remain the same regardless of the implementation.
<tr>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?> /index.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('home','','<?php echo $root; ?> /images/home1.gif',1)">
<img border="0"
src="<?php echo $root; ?>/images/home<?php echo $home; ?>.gif"
alt="Home" name="home">
</a>
</td>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/about.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('about','','<?php echo $root; ?>/images/about1.gif',1)">
<img border="0"
src="<?php echo $root; ?>/images/about<?php echo $about; ?>.gif"
alt="About" name="about">
</a>
</td>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/contact.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('contact','','<?php echo $root; ?>/images/contact1.gif',1)">
<img border="0"
src="<?php echo $root; ?>/images/contact<?php echo $contact; ?>.gif"
alt="Contact" name="contact">
</a>
</td>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/products.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('products','','<?php echo $root; ?>/images/products1.gif',1)">
<img border="0"
src="<?php echo $root; ?>/images/products<?php echo $products; ?>.gif"
alt="products" name="products">
</a>
</td>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/services.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('services','','<?php echo $root; ?>/images/services1.gif',1)">
<img border="0" src="<?php echo $root; ?>/images/services<?php echo $services; ?>.gif"
alt="Services" name="services">
</a>
</td>
</tr>
The thing to look for in each table cell definition above is the snippet that echoes the flags set in the if block. Toward the end of the line in the first table cell, for example, you see the following:
<img border="0"
src="<?php echo $root; ?>/images/home<?php echo $home; ?>.gif"
alt="Home" name="home">
Initially, we're setting the image source to "home.gif," since by default, the $home variable has no value to print out. If the $home flag was set to 1 in the if block above, however, when we echo the variable, we echo a 1, thus changing the image source to "home1.gif." And voila -- the URL sniffer has determined that we're on the home page and has highlighted the appropriate nav so that visitors always know what site section they're in.
Now, imagine we've got a slightly more complex site with some files in the document root and some in subdirectories. The principle is the same, but the if block is a little more complex.
<?php
if(eregi("about",$path[1])
{
$about=1;
if(eregi("company.php",$path[0]))
{
$about_company=1;
}
elseif(eregi("people.php",$path[0]))
{
$about_people=1;
}
}
elseif(eregi("products",$path[1])
{
$products=1;
if(eregi("hats.php",$path[0]))
{
$products_hats=1;
}
elseif(eregi("coats.php",$path[0]))
{
$products_coats=1;
}
}
elseif($path[1]=="")
{
if(eregi("index.php",$path[0]))
{
$home=1;
}
elseif($path[0]=="")
{
$home=1;
}
elseif(eregi("about.php",$path[0]))
{
$about=1;
}
elseif(eregi("contact.php",$path[0]))
{
$contact=1;
}
elseif(eregi("products.php",$path[0]))
{
$products=1;
}
elseif(eregi("services.php",$path[0]))
{
$services=1;
}
}
?>
In this example, we're looking at the second component of the path -- which, since we reversed the array above, represents the directory of the file being requested -- to get the current subdirectory, and we're setting the appropriate flag to 1. Then we're entering a nested if block that checks the first path component to see which page within a given subsection the visitor is currently browsing.
So if the URL is http://www.yourdomain.com/about/company.php, then the $about flag and the $about_company flag will be set to 1. We can use these flags in our nav and our subnav to highlight the current section and page. You can see here the value of reversing the $path array.
Doing so allows us to move from left to right (or 0 to n) in the array; not doing so would require us to use code more along the lines of:
if(eregi("about",$path[sizeof($path)-2))
{
//do stuff;
}
Such code is certainly doable, but it's harder to read and debug.
If you're using subnav and sub-subnav, depending upon what your site template looks like, you may wish to add some complexity to the way your top and bottom templates are built, but it's nothing our little script can't handle. If you're displaying all subnav on all pages, you simply print out all nav in your main include templates, but suppose you wish to restrict the display of subnav.
For example, imagine that you wish to display subnav for the about section only on pages that pertain to the about section. The first step would be to break your about subnav out into a separate include file. I imagine the include would look something like the following:
<table>
<tr>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/about/company.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('about_company','','<?php echo $root; ?>/images/about_company1.gif',1)">
<img border="0" src="<?php echo $root; ?>/images/about_company<?php echo $about_company; ?>.gif"
alt="Company" name="about_company">
</a>
</td>
</tr>
<tr>
<td align="left" valign="top" bgcolor="#000000">
<a href="<?php echo $root; ?>/about/people.php"
onMouseOut="MM_swapImgRestore()"
onMouseOver="MM_swapImage('about_people','','<?php echo $root; ?>/images/about_people1.gif',1)">
<img border="0" src="<?php echo $root; ?>/images/about_people<?php echo $about_people; ?>.gif"
alt="People" name="about_people">
</a>
</td>
</tr>
</table>
Note that the variable names here correspond to those in the main if block. Provided the if block is evaluated before the include is processed, the variables should pass through, and this code should work as well as the main nav code. In order to determine whether or not to display the subnav, you'd simply add the following line to your template in the appropriate spot (presumably right underneath the main about navigation graphic:
<?php
if($about==1)
{
include "about.inc.php";
}
?>
If you start using subnav and subdirectories, you'll want to be careful about how you include files. The block above will work fine provided "about.inc.php" can be located in the current directory. But what if it's not? I usually add a line like
$server_path="/full/path/to/document_root";
to the top of my file (you'll see it in the first code sample given above). Using this variable in conjunction with any include statements will guarantee that any time you're including a file, you're doing so with an absolute path, preventing ugly errors as a result of relative path issues.
Even for sites whose scope is broader than a 5-10 page online brochure, this little trick can be a handy tool for developers who want a quick solution for building a simple template-driven site without all the overhead and headache of a more involved system.
Objections might be raised that since variables are being hard coded into the template and must correlate with variables hard-coded in the main if block, this system is inelegant and not, strictly speaking, dynamic.
For my purposes, at any rate, it has proven a useful way of maintaining consistency across small-to-mid sized sites without having to hard code graphics references in static pages sitewide and without having to resort to some of the more beastly systems that can require more work up front and more difficult maintenance throughout the life of the site.
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