Professional Search Engine Optimization (Seo). Developer’s Guide to SEO

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You should at least provide a link back to the home page, and ideally to some more relevant parent

page. Otherwise, the user may be completely lost and will proceed to the nearest back button.

It is not always desirable to have a popup spidered by a search engine. Between the navigational con-

cerns, and the fact that popups very often do not contain substantial information, it may be wiser not

to. Unless the popup has substantial information, we advise excluding the popups from the spiders’

view entirely.

You can obtain the page from which the user navigated to the popup by reading the

$_SERVER[‘HTTP_

REFERER’]

header value. This information allows you to show navigational elements only if the user

has arrived from an external web site, such as a SERP.

This method is not 100% reliable, because some firewall applications block the REFERER information.

Also, if the referring page is secured via HTTPS, the REFERER information won’t be available. In this

exercise, when there is no REFERER data, err on the safe side and display the navigational elements.

You can try out this technique by going through a short exercise.

Implementing Spiderable Popups

Add a link to your popup file in your

catalog.php

script, as highlighted in the following code

snippet. Note that this assumes you’re working on the code that you built in the previous chap-

ters. If you don’t have it ready, feel free to use the code download of this chapter.

<?php

// load the URL factory library

require_once ‘include/url_factory.inc.php’;

...

<li>

<a href=”<?php echo make_category_product_url(“Friends’ Shed”, 2, “PHP

E-Commerce Book”, 42); ?>”>

Friends’ Shed: PHP E-Commerce Book

</a>

</li>

</ul>

<a href=”popup.php” target=”_blank”>Find more about Professional Search

Engine Optimization with PHP!</a>

</center>

</body>

</html>

Load

http://seophp.example.com/catalog.html

to ensure your script loads correctly and

displays the new link, as shown in Figure 6-1. Note that this exercise assumes you have built

your simple catalog as shown in Chapter 3.

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Chapter 6: SE-Friendly HTML and JavaScript

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