Chapter 1 Introduction to PHP...

What is PHP?

PHP is probably the most popular scripting language on the web. It is used to enhance web pages. With PHP, you can do things like create username and password login pages, check details from a form, create forums, picture galleries, surveys, and a whole lot more. If you've come across a web page that ends in PHP, then the author has written some programming code to liven up the plain, old HTML.
PHP is known as a server-sided language. That's because the PHP doesn't get executed on your computer, but on the computer you requested the page from. The results are then handed over to you, and displayed in your browser. Other scripting languages you may have heard of are ASP, Python and Perl. (You don't need to know any of these to make a start on PHP. In fact, these tutorials assume that you have no programming experience at all.)
The most popular explanation of just what PHP stands for is "Hypertext Pre-processor". But that would make it HPP, surely? An alternative explanation is that the initials come from the earliest version of the program, which was called Personal Home Page Tools. At least you get the letters "PHP" in the right order!
But PHP is so popular that if you're looking for a career in the web design/web scripting industry then you just have to know it! In these tutorials, we'll get you up and running. And, hopefully, it will be a lot easier than you think.

Course Files

To follow along with these tutorials, you'll need our Home and Learn Course files. These can be downloaded from the following address:
Download the PHP Course Files
You'll also need to have a server, to test your scripts. Don't worry, though - we've found an easy way to get a server up and running on your own PC.

What you need to get started with PHP

Before you can write and test your PHP scripts, there's one thing you'll need - a server! Fortunately, you don't need to go out and buy one. In fact, you won't be spending any extra money. That's why PHP is so popular! But because PHP is a server-sided scripting language, you either have to get some web space with a hosting company that supports PHP, or make your computer pretend that it has a server installed. This is because PHP is not run on your PC - it's executed on the server. The results are then sent back to the client PC (your computer).
Don't worry if this all sounds a little daunting - we've come across an easier way to get you up and running. We're going to be using some software called Wampserver. This allows you to test your PHP scripts on your own computer. It installs everything you need, if you have a Windows PC. We'll explain how to get it installed in a moment, and where to get it from. But just a word for non-windows users.

Apple Users

If you have OS X, then try these sites to get up and running with PHP:
What you're doing here is getting the apache server up and running, so that you can run PHP scripts offline. Pay particular attention to where files are stored, and to the "localhost" address.

Linux Users

There are quite a few sites out there to help Linux users get up and running with the Apache server and PHP. Here are three sites that are worth checking out:
If you know any better ones, we'd be interested in hearing from you!

Windows Users

OK, back to Wampserver and Windows. First, you need to download the software. You can get it from here (this site is nothing to do with ours, by the way):
Be sure to click the link for Presentation, as well as the link for Downloads. The Presentation page shows you how to install the file.

Installing and Testing Wampserver

Hopefully, you have now downloaded and installed Wampserver. This will give you a server on your own PC (Windows users), somewhere you can test your scripts. If you haven't yet downloaded the Wampserver software, you can download it here:
If the installation went well, you should have an new icon in the bottom right, where the clock is:
Click the icon to see the menu above.
From here, you can stop the server, exit it, view help files, and see the configuration pages.
Click on localhost, though, and you'll see this page appear: (Localhost just refers to the server running on your own computer. Another way to refer to your server is by using the IP address
Click the link under Tools that says phpinfo(). If all went well, you should be looking at the following page (The one below is a different php version, but don't worry about this - as long as you see something):
The info.php page (click to open in a new window 66K)
If you saw the above page, then congratulations! Your PHP server is up and running, and you can make a start scripting PHP pages.


If you don't see the info.php page, then you will need to refer to the wampserver forums. The page you need is here:
Hopefully, your question will already have been asked an answered. (Unfortunately, we can't answer questions about Wampserver, as it's not our software.)

Saving your PHP files

Whenever you create a new PHP page, you need to save it in your WWW directory. You can see where this is by clicking its item on the menu:
When you click on www directory, you should see an explorer window appear. This one is from Windows Vista: (You'll probably have only two files, index and testmysql.)
This www folder for Wampserver is usally at this location on your hard drive:
Bear this in mind when you click File > Save As to save your PHP scripts.

Launching your PHP scripts

Suppose you have created a php script called test1.php. To launch this script, you need to add the script name after localhost in your browser. So instead of this:
You would type this:
You don't type the name of the wamp folder, however. This would be wrong, for example:
As too would this:
Your server knows where the www folder is, so you don't have to type it out: just add the script name tolocalhost. Likewise, if you create a folder under www then you'd just type this:
OK, we'll assume that everything is now up and running.

PHP Variables

A variable is just a storage area. You put things into your storage areas (variables) so that you can use and manipulate them in your programmes. Things you'll want to store are numbers and text.
If you're ok with the idea of variables, then you can move on. If not, think of them like this. Suppose you want to catalogue your clothing collection. You enlist two people to help you, a man and a woman. These two people are going to be your storage areas. They are going to hold things for you, while you tally up what you own. The man and the woman, then, are variables.
You count how many coats you have, and then give these to the man. You count how many shoes you have, and give these to the woman. Unfortunately, you have a bad memory. The question is, which one of your people (variables) holds the coats and which one holds the shoes? To help you remember, you can give your people names! You could call them something like this:
But it's entirely up to you what names you give your people (variables). If you like, they could be called this:
But because your memory is bad, it's best to give them names that help you remember what it is they are holding for you. (There are some things your people balk at being called. You can't begin their names with an underscore (_), or a number. But most other characters are fine.)
OK, so your people (variables) now have name. But it's no good just giving them a name. They are going to be doing some work for you, so you need to tell them what they will be doing. The man is going to be holding the coats. But we can specify how many coats he will be holding. If you have ten coats to give him, then you do the "telling" like this:
mr_coats = 10
So, the variable name comes first, then an equals sign. After the equals sign, you tell your variable what it will be doing. Holding the number 10, in our case. (The equals sign, by the way, is not really an equals sign. It's called an assignment operator. But don't worry about it, at this stage. Just remember that you need the equals sign to store things in your variables.)
However, you're learning PHP, so there's something missing. Two things, actually. First, your people (variables) need a dollar sign at the beginning (people are like that). So it would be this:
$mr_coats = 10
If you miss the dollar sign out, then your people will refuse to work! But the other thing missing is something really picky and fussy - a semi-colon. Lines of code in PHP need a semi-colon at the end:
$mr_coats = 10;
If you get any parse errors when you try to run your code, the first thing to check is if you've missed the semi-colon off the end. It's very easy to do, and can be frustrating. The next thing to check is if you've missed out a dollar sign. But back to our people (variables).
So the man is holding ten coats. We can do the same thing with the other person (variable):
$mrs_shoes = 25;
So, $mrs_shoes is holding a value of 25. If we then wanted to add up how many items of clothes we have so far, we could set up a new variable (Note the dollar sign at the begining of the new variable):
We can then add up the coats and the shoes. You add up in PHP like this:
$total_clothes = $mr_coats + $mrs_shoes;
Remember, $mr_coats is holding a value of 10, and $mrs_shoes is holding a value of 25. If you use a plus sign, PHP thinks you want to add up. So it will work out the total for you. The answer will then get stored in our new variable, the one we've called $total_clothes. You can also add up like this:
$total_clothes = 10 + 35;
Again, PHP will see the plus sign and add the two together for you. Of course, you can add up more than two items:
$total_clothes = 10 + 35 + 7 + 38 + 1250;
But the idea is the same - PHP will see plus signs and then add things up. The answer is then stored in your variable name, the one to the left of the equals sign.


If you don't see the info.php page, then you will need to refer to the wampserver forums. The page you need is here: