Before you start using PHP includes, make sure that your web host or server can handle PHP files. Secondly, when you are using PHP includes on any pages, make sure the extension of those page is “.php” instead of “.html”. By using this PHP include script, once uploaded to the web, all of your files will merge appropriately to form one page.
Here’s how the PHP code looks like:
<?php include("filename.php"); ?>
The code can be pasted into sidebars, header, tables and anywhere you like.
Change the "filename" to anything you like, to make things easier to remember, it is suggested that you give it a name which correlates to the content you will be putting in it. For example if it is “header.php” then the file should be made especially for header. If the file contains advertisements for your site, then you can name it “ads.php”.
Next, you will want to create a page where the content of this page will appear in the page that contains the PHP include code. Make sure you save it with the exact same name you assigned to the code above, otherwise the script wont work.
Sometimes the path names doesn’t work and therefore you need to use alternative way, that is using the URL in the include instead, like this:
<?php include("http://www.domainname.com/directory/filename.php"); ?>
Using this method is less efficient in terms of server resources because (just like a browser) it has to create an HTTP session, get the file and then pull it in (even both of them located at the same server). This method of course is slower than using a pathname.
You can include files with .html, .php, .txt, .asp and other extensions.