Intro to PHP for Students and professionals

PHP
PHP
SALVADOR V. BRIONES II
Institute of Information Technology
Partido State University

Apache Web server
Apache Web server
 Often referred to as simply Apache, a
public-domain open source Web server
developed by a loosely-knit group of
programmers. The first version of
Apache, based on the NCSA httpd Web
server, was developed in 1995.

Apache cont’d:
Apache cont’d:
 Core development of the Apache Web
server is performed by a group of about 20
volunteer programmers, called the Apache
Group. However, because the source code
is freely available, anyone can adapt the
server for specific needs, and there is a
large public library of Apache add-ons. In
many respects, development of Apache is
similar to development of the Linux
operating system.

Apache cont’d:
Apache cont’d:
 The original version of Apache was written for
UNIX, but there are now versions that run
under OS/2, Windows and other platforms.
 The name is a tribute to the Native American
Apache Indian tribe, a tribe well known for its
endurance and skill in warfare. A common
misunderstanding is that it was called Apache
because it was developed from existing NCSA
code plus various patches, hence the name a
patchy server, or Apache server.

What is PHP?
What is PHP?
 Hypertext Pre-processor (PHP) is a server-
side scripting language, and server-side scripts
are special commands you must place in Web
pages. Those commands are processed before
the pages are sent from your Server to the
Web browser of your visitor. A typical PHP
files will content commands to be executed in
the server in addition to the usual mixture of
text and HTML (Hypertext Markup Language)
tags.

 When you type a URL in the Address box or click a
link on a Web page, you're asking a Web server on a
computer somewhere to send a file to the Web
browser (sometimes called a "client") on your
computer. If that file is a normal HTML file, it looks
exactly the same when your Web browser receives it
as it did before the Web server sent it. After receiving
the file, your Web browser displays its contents as a
combination of text, images, and sounds. In the case of
an PHP page, the process is similar, except there's an
extra processing step that takes place just before the
Web server sends the file.

 To distinguish them from normal HTML
pages, PHP files are usually given the
".php" extension.

What Can You Do with PHP?
What Can You Do with PHP?
There are many things you can do
with PHP.
◦ You can display date, time, and other
information in different ways.
◦ You can make a survey form and ask people
who visit your site to fill it out, send emails,
save the information to a file, etc

What Do PHP pages Look
What Do PHP pages Look
Like?
Like?
 The appearance of an PHP page depends on who
or what is viewing it. To the Web browser that
receives it, an Active Server Page looks just like a
normal HTML page. If a visitor to your Web site
views the source code of an PHP page, that's
what they see: a normal HTML page. However,
the file located in the server looks very
different. In addition to text and HTML tags, you
also see server-side scripts. This is what the PHP
page looks like to the Web server before it is
processed and sent in response to a request.

 Server-side scripts look a lot like HTML tags.
However, instead of starting and ending with
lesser-than ( < ) and greater-than ( > ) brackets,
they typically start with <?php or <? and will
typically end with ?>. The <?php or <? are
called anopening tags, and the ?> is called a
closing tag. In between these tags are the
server-side scripts. You can insert server-side
scripts anywhere in your Web page--even
inside HTML tags.

HISTORY OF PHP
HISTORY OF PHP
 [1995] PHP TOOLS
◦ Personal Home Page Tools
◦ Developed by Rasmus Lerdorf
◦ Initially created as a set of PERL scripts to
track accesses to his online resume
◦ Lerdorf chose to publicly release the source
code

History of PHP
History of PHP
 [1995] PHP/FI 1.0
◦ Personal Home Page / Form Interpreter
◦ Database connectivity was added,
implementing it in C language
◦ Enabled the development of simple dynamic
web applications
◦ Features: variables, html-embedded syntax,
form handling

History of PHP
History of PHP
 [1997] PHP / FI 2.0
◦ Approximately 50,000 pages (1% of the
internet) report usage
◦ Spent most of it’s life in beta

History of PHP
History of PHP
 [1998] PHP 3.0
◦ PHP: HYPERTEXT PREPROCESSOR
◦ Name was changed to make it sound more
useful for commercial usage
◦ First version resemble modern PHP
◦ Created by Andi Gutmans and Zeev Suraski
with help from Lerdorf
◦ Object-oriented and very consistent syntax
◦ Hundreds and thousands of Web sites
reporting its usage (10% of the internet)

History of PHP
History of PHP
 [1999] PHP 4.0
◦ “ZEND ENGINE” at the core
 Named after Zeev Suraski and Andi Gutmans

History of PHP
History of PHP
 [1999] PHP 4.0
◦ Handled third party databases more
efficiently
◦ Improved portability with a wider variety of
server compatibility
◦ Provides more secure transfer of
information
◦ Hundreds of thousands of users
◦ Several millions of pages report usage (20%
of the internet)

History of PHP
History of PHP
 [2004] PHP 5.0
◦ Powered by the new Zend Engine II
◦ New features:
 Robust support for object-oriented
programming
 Better support for MySQL
 Performance enhancements

PHP Language Basics
PHP Language Basics
 Basic Syntax
 Comments
 Variables
 Strings
 Concatenation Operators
 Operators
 Statements
 Arrays

Basic PHP Syntax
Basic PHP Syntax
A PHP scripting block always starts with <?
php and ends with ?>
Example:
1.<html>
2.<body>
3.<?php
4. echo "Hello World";
5.?>
6.</body>
7.</html>

Comments
Comments
// is used to make single-line comments
/* and */ is used to make a comment block
Example:
1.<html>
2.<body>
3.<?php
4. //This is a comment
5. /* This
6. is a
7. comment block
8. */
9.?>
10.</body>
11.</html>

PHP VARIABLES
PHP VARIABLES
Variables are used to store values
Variables in PHP start with a $ symbol
$var_name = value;
Example:
1.<?php
2. $stringVar = “Hello.”;
3. $numVar = 16;
4.?>

VARIABLE NAMING RULES
VARIABLE NAMING RULES
 Variable names must start with a letter or an
underscore “_”
 Variable names can only contain alpha-
numeric characters and underscores
 Variable names should not contain spaces. If
a variable name is more than two words, it
should be separated by an underscore
($a_variable) or by capitalization ($aVariable)

Strings
Strings
String variables are used for values that
contains characters strings.
Example:
1.<?php
2. $text = “Hello World!”;
3. echo $text;
4.?>
Output:
Hello World!

CONCATENATION OPERATOR
Used to put two or more string values
together.
Dot (.) operator is used to concatenate strings.
Example:
1.<?php
2. $txt1 = “String 1”;
3. $txt2 = “String 2”;
4. $txt3 = “1 2 3”;
5. echo $txt1 . “ ” . $txt2 . “ ” .
6. $txt3;
7.?>

 Output:
 String 1 String 2 1 2 3

OPERATORS
OPERATORS
 Arithmetic Operators
Operation Operator Example
Multiplication * $a * $b
Division / $a / $b
Modulus % $a % $b
Addition + $a + $b
Subtraction - $a - $b

OPERATORS
OPERATORS
 Assignment Operators
Assignment = $a = 5
Addition += $a += 5
Subtraction -= $a -= 5
Multiplication *= $a *= 5
Division /= $a /= 5
Concatenation .= $a .= “test”
Modulus %= $a %= 5

OPERATORS
OPERATORS
 Comparison Operators
Less than < $a < $b
Less than or
equal
<= $s <= $b
Greater than > $a > $b
Greater than
or equal
>= $a >= $b
Is equal to == $a == $b
Is not equal != $a != $b

OPERATORS
OPERATORS
 Logical Operators
Operator Description Example
&& and x=6
y=3
(x < 10 && y > 1)
returns true
|| or x=6
y=3
(x==5 || y==5)
returns false
! not x=6
y=3
!(x==y) returns true

CONDITIONAL STATEMENTS
if-else statement
 if (<test_expression>) conditional statement;
if-else statement
 if (<test_expression>) conditional statement;
else alternate statement;
if-elseif-else statement
 if (<test_expression1>) conditional statement;
elseif (<test_expression2>) conditional
statement;
……………..
else alternate statement;

Example [if-else statement]:
1.
<?php
2. $num = 7;
3. if ($num > 10)
4. echo $num . “ is greater than 10”;
5. else
6. echo $num . “ is less than 10”;
7.
?>
Output:
 7 is less than 10

Example [if-elseif-else statement]:
1.
<?php
2. $num = 10;
3. if ($num > 10)
4. echo $num . “ is greater than 10”;
5. else if ($num < 10)
6. echo $num . “ is less than 10”;
7. else
8. echo $num . “ is equal to 10”;
9.
?>
Output:
 10 is equal 10

LOOP STATEMENTS
LOOP STATEMENTS
 while statement
◦ while (test_expression)
{statements to be executed repeatedly}
 Example:
1.
<?php
2. $x = 1;
3. while ($x <= 5)
4. {
5. echo “x = ” . $x . “<br>”;
6. $x++;
7. }
8.
?>

LOOP STATEMENTS
LOOP STATEMENTS
 Output:
 x = 1
x = 2
x = 3
x = 4
x = 5

LOOP STATEMENTS
LOOP STATEMENTS
 do-while statement
◦ do{
statement to execute once, then
repeatedly
}while (test_expression);
 Example:
1.
<?php
2. $x = 1;
3. do{
4. echo “x = ” . $x . “<br>”;
5. $x++;
6. while($x <= 5);
7.
?>

LOOP STATEMENTS
LOOP STATEMENTS
for statement
 for (initialization; test_expression; update)
statements to repeat
Example:
1.
<?php
2. for ($x = 0; $x < 5; $x++)
3. echo “Hello <br>”;
4.
?>
Output:
Hello
Hello
Hello
Hello
Hello

ARRAYS
ARRAYS
 Numeric Arrays – arrays with numeric
ID keys
 How to create a Numeric Array:
◦ Example 1:
$days = array(“Monday”, “Tuesday”,
“Wednesday”);
◦ Example 2:
$days[0] = “Monday”;
$days[1] = “Tuesday”;
$days[2] = “Wednesday”;

ARRAYS
ARRAYS
1.<?php
2. $days[0] = “Monday”;
3. $days[1] = “Tuesday”;
4. $days[2] = “Wednesday”;
5. echo $days[0] . “ ” . $days[1]
. “ ” .
6. $days[2];
7.?>
 Output:
Monday Tuesday Wednesday

ARRAYS
ARRAYS
1.<?php
2. $days = array(“Monday”,
“Tuesday”,
3. “Wednesday”);
4. echo $days[0] . “ ” . $days[1]
. “ ” .
5. $days[2];
6.?>
 Output:
Monday Tuesday Wednesday

FUNCTIONS
FUNCTIONS
 A function is a block of code
 Contains zero or more parameters
 Performs a task

CREATING FUNCTIONS
CREATING FUNCTIONS
All functions start with “function”
Give it a name (identifier)
The block of code is enclosed in curly braces
“{” and “}”
SYNTAX:
Function <identifier> (<parameter/s>)
{
body of the function
}

FUNCTIONS
FUNCTIONS
Example:
1.<?php
2. function printMyName()
3. {
4. echo “Jen”;
5. }
6.
7. printMyName();
8.?>
Output: Jen

FUNCTIONS
FUNCTIONS
Example:
1.<?php
2. function printMyName($name)
3. {
4. echo $name;
5. }
6.
7. echo “My name is ”;
8. printMyName(“Jen”);
9.?>
Output: My name is Jen

FUNCTIONS
FUNCTIONS
Example:
1.<?php
2. function add($x, $y)
3. {
4. $sum = $x + $y;
5. return $sum;
6. }
7.
8. echo “The sum of 6 and 16 is ”
9. . add(6, 16);
10.?>
Output: The sum of 6 and 16 is 22

FORMS
FORMS
<form> is just another kind of HTML tag
HTML forms are used to create (rather
primitive) GUIs on Web pages
 Usually the purpose is to ask the user for
information
 The information is then sent back to the server
A form is an area that can contain form
elements
 The syntax is: <form parameters> ...form
elements... </form>
 Form elements include: buttons, checkboxes, text
fields, radio buttons, drop-down menus, etc
Other kinds of HTML tags can be mixed in with the form
elements
 A form usually contains a Submit button to send
the information in he form elements to the server

THE <FORM> TAG
THE <FORM> TAG
 The <form arguments> ... </form> tag encloses
form elements (and probably other HTML as well)
 The arguments to form tell what to do with the
user input
◦ action="url" (required)
 Specifies where to send the data when the Submit button is
clicked
◦ method="get" (default)
 Form data is sent as a URL with ?form_data info appended to
the end
◦ method="post"
 Form data is sent in the body of the URL request
 Cannot be bookmarked by most browsers
◦ target="target"
 Tells where to open the page sent as a result of the request
 target= _blank means open in a new window
 target= _top means use the same window

THE <INPUT> TAG
THE <INPUT> TAG
 Most, but not all, form elements use the input
tag, with a type="..." argument to tell which kind
of element it is
◦ type can be text, checkbox, radio, password, hidden, submit, reset, button,
file, or image
 Other common input tag arguments include:
◦ name: the name of the element
◦ value: the “value” of the element; used in different ways for different values
of type
◦ readonly: the value cannot be changed
◦ disabled: the user can’t do anything with this element

TEXT INPUT
TEXT INPUT
A text field:
<input type="text" name="textfield" value="with an initial value">
A multi-line text field
<textarea name="textarea" cols="24" rows="2">Hello</textarea>
A password field:
<input type="password" name="textfield3" value="secret">

Buttons
Buttons
A submit button:
<input type="submit" name="Submit" value="Submit">
A reset button:
<input type="reset" name="Submit2" value="Reset">
 submit: send data
 reset: restore all form elements
to their initial state

Checkboxes
Checkboxes
A checkbox:
<input type="checkbox" name="checkbox”
value="checkbox" checked>
type: "checkbox"
name: used to reference this form element from
JavaScript
value: value to be returned when element is checked
Note that there is no text associated with the checkbox
—you have to supply text in the surrounding HTML

Radio Buttons
Radio Buttons
Radio buttons:<br>
<input type="radio" name="radiobutton" value="myValue1">
male<br>
<input type="radio" name="radiobutton" value="myValue2"
checked>
female
•If two or more radio buttons have the same name, the
user can only select one of them at a time
•This is how you make a radio button “group”
•If you ask for the value of that name, you will get the
value specified for the selected radio button
•As with checkboxes, radio buttons do not contain any

AN EXAMPLE
AN EXAMPLE
<html>
<head>
<title>Get Identity</title>
</head>
<body>
<p><b>Who are you?</b></p>
<form method="post" action="">
<p>Name:
<input type="text" name="textfield">
</p>
<p>Gender:
<input type="radio" name="gender" value="m">Male
<input type="radio" name="gender" value="f">Female</p>
</form>
</body>
</html>

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