introduction to server-side scripting

Introduction to
Server-side
Scripting
CSC318
DYNAMIC WEB
APPLICATION
DEVELOPMENT

• How does a Server-Side Page Work
• Introduction to PHP
CONTENT

• "Server-side" just means that the control of the
script is handled by the Web Crossing server rather
than running a script on each user's personal
computer.
• Web Crossing runs the scripts and sends standard
HTML (web pages) to each user's browser.
• All the end user's browser has to worry about is
displaying the results and does not have to worry
about the underlying script used to generate the
web pages.
How does a Server-Side Page
Work

Examples of Server-side
Scripting Language
• ASP (*.asp)
• ASP.NET (*.aspx)
• ColdFusion Markup Language (*.cfm)
• JavaServer Pages
• PHP (*.php)
• Python (*.py)
• Ruby (*.rb, *.rbw)
• SMX (*.smx)
• Lasso (*.lasso)
• Tcl (*.tcl)
• WebDNA (*.dna,*.tpl)

Introduction to PHP
• PHP stands for PHP: Hypertext Preprocessor
• PHP is a server-side scripting language, like ASP
• PHP scripts are executed on the server
• PHP supports many databases (MySQL, Informix,
Oracle, Sybase, Solid, PostgreSQL, Generic ODBC,
etc.)
• PHP is an open source software (OSS)
• PHP is free to download and use

Introduction to PHP
• PHP files may contain text, HTML tags and scripts
• PHP files are returned to the browser as plain
HTML
• PHP files have a file extension of ".php", ".php3",
or ".phtml"
• PHP is compatible with almost all servers used
today (Apache, IIS, etc.)
• PHP is FREE to download from the official PHP
resource: www.php.net

Basic PHP Syntax
• A PHP scripting block always starts with <?php and ends
with ?>. A PHP scripting block can be placed anywhere
in the document.
• On servers with shorthand support enabled you can
start a scripting block with <? and end with ?>.
• However, for maximum compatibility, we recommend
that you use the standard form (<?php) rather than the
shorthand form.
<?php
:
?>

Example
• Each code line in PHP must end with a semicolon. The
semicolon is a separator and is used to distinguish one set of
instructions from another.
• Two basic statements to output text with PHP: echo and print.
• Note:
The file must have the .php extension. In file with the .html
extension, the PHP code will not be executed.

Comments in PHP
• In PHP, we use // to make a single-line comment
or /* and */ to make a large comment block.
• Example:
<html> <body>
<?php
//This is a comment
/*
This is
a comment
block
*/
?> </body> </html>

Variables in PHP
• Variables are used for storing a values, like text strings,
numbers or arrays.
• When a variable is set it can be used over and over again
in your script
• All variables in PHP start with a $ sign symbol.
• The correct way of setting a variable in PHP:
$var_name = value;
• Example:
<?php
$txt = "JKA";
$number = 1517;
?>

Variable Naming Rules
• A variable name must start with a letter or an
underscore "_"
• A variable name can only contain alpha-numeric
characters and underscores (a-Z, 0-9, and _ )
• A variable name should not contain spaces. If a
variable name is more than one word, it should
be separated with underscore ($my_string), or
with capitalization ($myString )

Strings in PHP
• String variables are used for values that contains
character strings.
• After we create a string we can manipulate it. A
string can be used directly in a function or it can
be stored in a variable.
• Example:

The Concatenation Operator
• The concatenation operator (.) is used to put two
string values together.
• To concatenate two variables together, use the
dot (.) operator.
• Example:

Using the strlen() function
• The strlen() function is used to find the length of a string.
• The length of a string is often used in loops or other functions,
when it is important to know when the string ends. (i.e. in a loop,
we would want to stop the loop after the last character in the
string)
• Example:

Using the strpos( ) function
• The strpos() function is used to search for a string or
character within a string.
• If a match is found in the string, this function will return
the position of the first match. If no match is found, it
will return FALSE.
• Example:
• As you see the position of the string "world" in our
string is position 6. The reason that it is 6, and not 7, is
that the first position in the string is 0, and not 1.

Conditional statement
• The If...Else Statement
– Syntax:
– Example:

Conditional statement
• The ElseIf Statement
– Syntax:
– Example:

Looping
• In PHP we have the following looping
statements:
a) while - loops through a block of code if and as long
as a specified condition is true
b) do...while - loops through a block of code once, and
then repeats the loop as long as a special condition
is true
c) for - loops through a block of code a specified
number of times
d) foreach - loops through a block of code for each
element in an array

The for Statement
• Syntax:
– init: Is mostly used to set a counter, but can be any code
to be executed once at the beginning of the loop
statement.
– cond: Is evaluated at beginning of each loop iteration. If
the condition evaluates to TRUE, the loop continues and
the code executes. If it evaluates to FALSE, the execution
of the loop ends.

The for Statement
– incr: Is mostly used to increment a counter, but can
be any code to be executed at the end of each loop.
• Example:

The while Statement
• Syntax:
• Example:

The do...while Statement
• Syntax:
• Example:

PHP Functions
• A function is a block of code that can be executed
whenever we need it. Creating PHP functions:
All functions start with the word "function()"
Name the function - It should be possible to understand
what the function does by its name. The name can start
with a letter or underscore (not a number)
Add a "{" - The function code starts after the opening
curly brace
Insert the function code
Add a "}" - The function is finished by a closing curly brace

PHP Functions - Adding
parameters
• To add more functionality to a function, we can
add parameters. A parameter is just like a
variable.
• Example:

PHP Functions - Return values
• Functions can also be used to return values.
• Example:

introduction to server-side scripting

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