PHP Tutorial - Learn PHP
If you want to learn the basics of PHP, then you've come to the right place. The goal of this tutorial is to teach you the basics of PHP so that you can:

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Customize PHP scripts that you download, so that they better fit your needs. Begin to understand the working model of PHP, so you may begin to design your own PHP projects. Give you a solid base in PHP, so as to make you more valuable in the eyes of future employers.

PHP stands for PHP Hypertext Preprocessor.

PHP - What is it?
Taken directly from PHP's home, PHP.net, "PHP is an HTML-embedded scripting language. Much of its syntax is borrowed from C, Java and Perl with a couple of unique PHP-specific features thrown in. The goal of the language is to allow web developers to write dynamically generated pages quickly." This is generally a good definition of PHP. However, it does contain a lot of terms you may not be used to. Another way to think of PHP is a powerful, behind the scenes scripting language that your visitors won't see! When someone visits your PHP webpage, your web server processes the PHP code. It then sees which parts it needs to show to visitors(content and pictures) and hides the other stuff(file operations, math calculations, etc.) then translates your PHP into HTML. After the translation into HTML, it sends the webpage to your visitor's web browser.

PHP - What's it do?
It is also helpful to think of PHP in terms of what it can do for you. PHP will allow you to:

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Reduce the time to create large websites. Create a customized user experience for visitors based on information that you have gathered from them. Open up thousands of possibilities for online tools. Check out PHP - HotScripts for examples of the great things that are possible with PHP. Allow creation of shopping carts for e-commerce websites.

What You Should Know
Before starting this tutorial it is important that you have a basic understanding and experience in the following:

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HTML - Know the syntax and especially HTML Forms. Basic programming knowledge - This isn't required, but if you have any traditional programming experience it will make learning PHP a great deal easier.

Tutorial Overview
This tutorial is aimed at the PHP novice and will teach you PHP from the ground up. If you want a drivethrough PHP tutorial this probably is not the right tutorial for you. Remember, you should not try to plow through this tutorial in one sitting. Read a couple lessons, take a break, then do some more after the information has had some time to sink in.

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PHP - Syntax
Before we talk about PHP's syntax, let us first define what syntax is referring to.

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Syntax - The rules that must be followed to write properly structured code.

PHP's syntax and semantics are similar to most other programming languages (C, Java, Perl) with the addition that all PHP code is contained with a tag, of sorts. All PHP code must be contained within the following...

PHP Code: or the shorthand PHP tag that requires shorthand support to be enabled on your server...

If you are writing PHP scripts and plan on distributing them, we suggest that you use the standard form (which includes the ?php) rather than the shorthand form. This will ensure that your scripts will work, even when running on other servers with different settings.

How to Save Your PHP Pages
If you have PHP inserted into your HTML and want the web browser to interpret it correctly, then you must save the file with a .php extension, instead of the standard .html extension. So be sure to check that you are saving your files correctly. Instead of index.html, it should be index.php if there is PHP code in the file.

Example Simple HTML & PHP Page
Below is an example of one of the easiest PHP and HTML page that you can create and still follow web standards.

PHP and HTML Code: My First PHP Page

Display:
Hello World! If you save this file and place it on PHP enabled server and load it up in your web browser, then you should see "Hello World!" displayed. If not, please check that you followed our example correctly. We used the PHP function echo to write "Hello World!" and we will be talking in greater depth about this PHP function and many others later on in this tutorial.

The Semicolon!
As you may or may not have noticed in the above example, there was a semicolon after the line of PHP code. The semicolon signifies the end of a PHP statement and should never be forgotten. For example, if we repeated our "Hello World!" code several times, then we would need to place a semicolon at the end of each statement.

PHP and HTML Code: My First PHP Page

Display:
Hello World! Hello World! Hello World! Hello World! Hello World!

White Space
As with HTML, whitespace is ignored between PHP statements. This means it is OK to have one line of PHP code, then 20 lines of blank space before the next line of PHP code. You can also press tab to indent your code and the PHP interpreter will ignore those spaces as well.

PHP and HTML Code: My First PHP Page

Display:
Hello World!Hello World! This is perfectly legal PHP code.

PHP - Variables
If you have never had any programming, Algebra, or scripting experience, then the concept of variables might be a new concept to you. A detailed explanation of variables is beyond the scope of this tutorial, but we've included a refresher crash course to guide you. A variable is a means of storing a value, such as text string "Hello World!" or the integer value 4. A variable can then be reused throughout your code, instead of having to type out the actual value over and over again. In PHP you define a variable with the following form:

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$variable_name = Value;

If you forget that dollar sign at the beginning, it will not work. This is a common mistake for new PHP programmers!

A Quick Variable Example
Say that we wanted to store the values that we talked about in the above paragraph. How would we go about doing this? We would first want to make a variable name and then set that equal to the value we want. See our example below for the correct way to do this.

PHP Code:

Note for programmers: PHP does not require variables to be declared before being initialized.

PHP Variable Naming Conventions
There are a few rules that you need to follow when choosing a name for your PHP variables.

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PHP variables must start with a letter or underscore "_". PHP variables may only be comprised of alpha-numeric characters and underscores. a-z, A-Z, 0-9, or _. Variables with more than one word should be separated with underscores. $my_variable Variables with more than one word can also be distinguished with capitalization. $myVariable

PHP - Echo
As you saw in the previous lesson, the PHP function echo is a means of outputting text to the web browser. Throughout your PHP career you will be using the echo function more than any other. So let's give it a solid perusal!

Outputting a String
To output a string, like we have done in previous lessons, use the PHP echo function. You can place either a string variable or you can use quotes, like we do below, to create a string that the echo function will output.

PHP Code:

Display:
Hello!

I love using PHP!
In the above example we output "Hello!" without a hitch. The text we are outputting is being sent to the user in the form of a web page, so it is important that we use proper HTML syntax! In our second echo statement we use echo to write a valid Header 5 HTML statement. To do this we simply put the at the beginning of the string and closed it at the end of the string. Just because you're using PHP to make web pages does not mean you can forget about HTML syntax!

Careful When Echoing Quotes!
It is pretty cool that you can output HTML with PHP. However, you must be careful when using HTML code or any other string that includes quotes! The echo function uses quotes to define the beginning and end of the string, so you must use one of the following tactics if your string contains quotations:

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Don't use quotes inside your string Escape your quotes that are within the string with a slash. To escape a quote just place a slash directly before the quotation mark, i.e. \" Use single quotes (apostrophes) for quotes inside your string.

See our example below for the right and wrong use of the echo function:

PHP Code:

Display:
Hello Bob. My name is: 4a

Echoing Variables and Text Strings
You can also combine text strings and variables. By doing such a conjunction you save yourself from having to do a large number of echo statements. Variables and text strings are joined together with a period( . ). The example below shows how to do such a combination.

PHP Code: