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PHP
PHP Hypertext Preprocessor
Reference : http://www.w3schools.com/php/php_intro.asp
Official Site : http://www.php.net
PHP Hypertext Preprocessor
What?
♦ Open source free to downloadfrom www.php.net
♦ Server-side script (similar to asp)executed at the server end (unlike javascript)
♦ Common uses
♦ Form-handling
♦ E-commerce
♦ Shopping-carts store information on the server
PHP Hypertext Preprocessor
PHP files
• Have file extension .phpe.g. index.php
• File contains text, html tags & scripts
• PHP codes enclosed in <?php ?> tags
• File MUST be parsed by web-server (cannot open directly in browser)
PHP Hypertext Preprocessor
PHP syntax
Simiar to C++• Statements end with semi-colon;• Case-sensitive• Same rules about variable names
1. No spaces
2. Must not begin with numbers
• Same logic & loop structureif ( ) { }
PHP Hypertext Preprocessor
PHPExample:
<html><head><script> window.status = 'hello';</script><body><?php echo "hello\n";?></body></html>
PHP Hypertext Preprocessor
PHPVariables
1. Prefixed with ‘$’
2. Begins with letters or underscore
3. Contains only a-z A-Z 0-9 _
4. No need to define type
Examples: $a1, $_x, $myVariable
$1a, $my name , $x.y
PHP Hypertext Preprocessor
PHPSuperglobal Variables
• $_GET
• $_POST
• $_REQUEST
• $_SERVER
PHP Hypertext Preprocessor
PHPSimple PHP commands
• echo
• print_r
• array( )
• count( $x)
PHP Hypertext Preprocessor
PHPArrays
A variable that stores multiple values
e.g. $scores
80 90 95 100 60
PHP Hypertext Preprocessor
PHPArrays
Two types of arrays
• indexed
• associative
PHP Hypertext Preprocessor
PHPArrays
Normal (indexed) array
- Each value is referenced by index numbers, starting from zero.
0 1 2 3 4
80 90 95 100 60Index numbers
values
<?php echo $scores[2]; ?>
PHP Hypertext Preprocessor
PHPArrays
Associative array
- Each value is referenced by text known as key.
CL EL HU MA SC
80 90 95 100 60keys
values
<?php echo $scores[" HU"]; ?>
PHP Hypertext Preprocessor
PHPArray defintion
<?php$scores1 = array(80, 90, 95, 100, 60);
$scores2 = array("CL"=>80, "EL"=>90, "HU"=>95, "MA"=>100, "SC"=>60);
?>
PHP Hypertext Preprocessor
PHPArrays
Debugging arrays
- The function “print_r” is used to display contents in an array.
<?php print_r $scores; ?>
PHP Hypertext Preprocessor
PHPArrays
The following system variables are associative arrays:
$_GET$_POST$_REQUEST$_SERVER$_SESSION
PHP Hypertext Preprocessor
☺PHP
