PHP: A Server-Side Scripting Language - History, Syntax, and Data Handling, Slides of Computer Programming

Download PHP: A Server-Side Scripting Language - History, Syntax, and Data Handling and more Slides Computer Programming in PDF only on Docsity!

Introduction to PHP and

Server Side Technology

PHP History

 Created in 1995  PHP 5.0 is the current version  It’s been around since 2004

The Basics of PHP Syntax

 PHP script always appears between  ****  PHP statements always end in a semi-colon  Comments have the same format as JavaScript  PHP IS CASE SENSITIVE

A First PHP Program

 As in  **

**

A First Server Round Trip

Using Forms (2)

 The following form posts to the page named Welcome.php ( action attribute)

** Name: Age:

**

A First Server Round Trip

Using Forms (3)

 Welcome.php contains the script to process the posted data **

Welcome ! You are years old.

**

GET and POST (Introduction)

 There are two basic ways to send data back to a Web server  We call these HTTP verbs  In all there are about 30 verbs  http://annevankesteren.nl/2007/10/http-methods  Both GET and POST send data to Web servers

HTTP GET

 GET sends is data through the URL itself as a query string  The URL looks something like this  http://localhost/PhpProjectDemo1/welcome.php ?fname=zaphod&age=  **** values appear after the?

 Data appears as key=value pairs

 A & separates each key=value pair

 You don’t write the URL – HTTP does!

HTTP GET and POST

(Comparison)

 GET

 Query strings are small (100 characters)  Posted data is visible  It’s possible to bookmark the page  PUT  Large data blocks can be posted  Posted data is hidden  Page cannot be bookmarked

Reading Posted Data

 $_GET and $_POST retrieve data send to the server via a GET or POST , respectively  They are built-in functions  Pass the ID of the input control as an argument

PHP Variables

 Like JavaScript, variables are ‘loosely typed’  Variables can be declared anywhere in a PHP script  Variable names  Must begin with a letter or underscore ‘_’ character  The following characters can be letters, numbers or the underscore  Variables cannot contain spaces

PHP Variables (Declaring)

 Variable declarations begin with the dollar sign ‘$’, followed by the variable name  An equals sign and value follow the declaration  Examples: $userName = “joe”; $pi = 3.14;

Using Numeric Variables (2)

 The following prints 10 + 100 because the value is quoted

$x = 10; $y = 100; print "$x + $y";

PHP Strings (Introduction)

 Strings work in PHP the same way they work in other languages  There are several string functions:  http://w3schools.com/php/php_ref_string.asp  The dot (.) is the concatenation operator