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Guide to PHP and MySQL (University at Buffalo Version)

Chapter 1: Introduction to PHP

PHP is a popular general-purpose scripting language that is especially suited to web development. (See PHP code runs on a web server unlike HTML or JavaScript which are handled by a web browser.

PHP code can be embedded in an HTML file usg the <?php and ?> tags.

Hello World!

Most beginning programmers start with the standard "Hello World" code:

An HTML/PHP Hello World Web Page

<!doctype html>
    <title>The name of this page</title>
    <p><?php echo("Hello World!"); ?></p>

Figure 1-1: Code for helloworld.php

The rendered web page would look like this:


Hello World!

Figure 1-2: Hello World PHP Page

PHP Comments

PHP provides a few different way to add comments to your code. You can use multi-line comments or inline (single line) comments or PHPDoc comments. Comments should be used to explain what your code is doing. Comments should be used to provide a description of each function including whether there are parameters and whther the function returns a value or not.

/* Assignment: Form Web Page
Author: Your Name Here
Date: Month Day, Year file was last edited
Editor: Notepad++ or TextWrangler or whatever editor you used

$i = 0; // Declare a variable named i to be used in a for loop and assign it a value of zero (0)

 * PHPDoc Commments
 * This function does something
 * @param none
 * @return none

function someName() {
  // some code

Figure 1-3: PHP Comments

Using download.php

Save this file (download.php) to your cda215 web space. Then in your HTML code use this line:

<a href="download.php?file=index.php">index.php</a><br/>
<a href="download.php?file=vars.php">vars.php</a><br/ >

Figure 1-3: Using download.php

Test to make sure it works for you.

Let's Get Started with Your First PHP Page!

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