Download - PHP OVERVIEW. C ONTENT Introduction of PHP History and development Basics of PHP programming
PHP OVERVIEW
CONTENT
Introduction of PHP
History and development
Basics of PHP programming
WHAT IS PHP ?
PHP = Hypertext preprocessor
Server side scripting language
Used for development of dynamical webpages Part of typical LAMP combination Linux, Apache, MySQL and PHP
Includes a command line scripting possibility Can be used in graphical applications
HOW IT WORKS
PHP code is usually embedded into HTML
Processing the code :1) The HTML code stands as it is
2) The PHP scripts are executed to create final HTML code
3) Both parts are combined and back
4) Resulting HTML is interpreted by a browser
ADVANTAGES OF PHP
Freely available The PHP group provides complete source
code free of charge Similar syntax to C, Pearl Works with many operating systems Can be deployed on many web servers Interacts with lots of databases It is supported by many providers of
webhosting
HISTORY – INITIAL DEVELOPMENT Originally created by Rasmus Lerdorf
PHP originally stood for Personal Home Page Replaces small set of Pearl scripts Used as a tool for observing traffic on webpage
PHP 2 (PHP/FI) First publicly released version (on June 8, 1995) Combination of Lerdorf’s Form Interpreter and
original binary from PHP Was able to communicate with databases Enabled the building of dynamical web
application included Perl-like variables, form handling, and
the ability to be embedded HTML
HISTORY – RELEASED VERSIONSPHP (PHP: Hypertext Preprocessor) was created by Rasmus Lerdorf in
1994. It was initially developed for HTTP usage logging and server-side form generation in Unix.
PHP 2 (1995) transformed the language into a Server-side embedded scripting language. Added database support, file uploads, variables, arrays, recursive functions, conditionals, iteration, regular expressions, etc.
PHP 3 (1998) added support for ODBC data sources, multiple platform support, email protocols (SNMP,IMAP), and new parser written by Zeev Suraski and Andi Gutmans .
PHP 4 (2000) became an independent component of the web server for added efficiency. The parser was renamed the Zend Engine. Many security features were added.
PHP 5 (2004) adds Zend Engine II with object oriented programming, robust XML support using the libxml2 library, SOAP extension for interoperability with Web Services, SQLite has been bundled with PHP
CURRENT VERSION - PHP 5
The most recent extension (the 5.2.6) was published on May 1, 2008
Uses enhanced Zend II engine
It includes : support for object-oriented programming, the PHP Data Objects extension (simplifies
accessing databases) numerous performance enhancements
WEBSITES USING PHP
More than 20 million Internet domains are hosted on servers with PHP installed
Significant examles User-facing portion of Facebook Wikipedia (MediaWiki) Yahoo! MyYearbook
WHAT DO YOU NEED TO WORK WITH PHP?
If your server supports PHP You don’t need anything Just create some .php files in your web directory
If your server does not support PHP, you must install PHP. Download PHP Download database (MySQL) Download server (Apache)
BASICS OF SYNTAX
Scripting block starts with <?php and ends with ?>
Each code line in PHP must end with a (;)
Comments // ,# comment /* comment */ Writing of the plain textEcho “text”print “text”
VARIABLES IN PHP
Each variable starts with $ symbol
Variable name can contain only a-Z,0-9,_
It does not need to be declared before its setting.
<?php $txt = "Hello World!"; $number = 16;
?>
VARIABLE TYPES
Numerical Integer – positive as well as negative, including 0 Float – real numbers, 14 digits accuracy
Logical Boolean - True x False, not case sensitive
Alphabetical String – set of characters
WORKING WITH VARIABLES
Settype($var, “integer”) allows you to set variable according to your wish
Gettype() write the type of variable
(.) Connects 2 variables of string type
strlen() finds the length of a string
PHP OPERATORS
LOGICAL OPERATORS
&& = and || = or
At least one of condition is fulfilled ! = not xor
Exactly one statement is evaluated as true
CONDITIONAL STATEMENTS
If/ else After each statement stands (;) If more than one command should be executed,
use curly braces { }
Switch / break Used for choosing one possibility from multiple
casesSwitch ($var )
{ case : “x” : echo “good”; break;default : echo “wrong input” ;}
ARRAYS IN PHP
Numeric array Each element of array has its ID number (first
0!!) $names = array("Petr“,"Joe"); $names[0] = "Petr";
Associative Arrays Each element is assigned its value $ages = array("Peter"=>32, "Joe"=>34); $ages['Peter'] = "32";
MULTIDIMENSIONAL ARRAYS
element of array is also an array
$families = array ("Griffin"=>array
( "Peter", "Lois", "Megan" ), "Soltis" =>array
(“Johny", "Morgan" ))
PHP LOOPING
while loops repeat until final condition is reached$i =1;while ($i<=10)
{ echo $i; $i++; }
do...while kind of reversed while function Do { code to be executed;} While(final condition);
PHP LOOPING
for Repeats the specific part of code so many times
we choose
for ($i=1; $i<=10; $i++)
Initial condition final condition running decsription
HTML INSIDE PHP
If inside quotes, the Html tags are returned as a text by PHP module
Treated as a HTML tag by
<?phpecho "<TR>
<TD>".$i."</TD><TD>".$i*$i."</TD></TR>\n";
?>
PHP FUNCTIONS
All function starts with function($parameter)
Requirements for naming functions are same as these for variables
The { mark opens the function code, while } mark closes it
It can have either defined or no parameter
More than 700 built-in functions available
PHP FORMS AND USER INPUT
Used to gain information from users by means of HTML
Information is worked up by PHP<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>
THE $_GET VARIABLE
Used to collect values from a form Displays variable names and values are in the
URL http://www.w3schools.com/welcome.php?
name=jo&age=39 Can send limited amount of information (max.
100 characters)<html>
<body>
Welcome <?php echo $_GET["name"]; ?> <br />
You are <?php echo $_GET["age"]; ?> years old
</body>
</html>
THE $_POST VARIABLE
Used to collect values from a form Information from a form is invisible No limits on the amount of information to be
send
<html>
<body>
Welcome <?php echo $_POST["name"]; ?><br />
You are <?php echo $_POST["age"]; ?> years old.
</body>
</html>