PHP stands for "Hypertext Preprocessor" ,it is a server scripting language.

What Can PHP Do?

• PHP can generate dynamic page content
• PHP can create, open, read, write, delete, and close files on the server
• PHP can collect form data
• PHP can send and receive cookies
• PHP can add, delete, modify data in your database
• PHP can be used to control user-access
• PHP can encrypt data

1> Basic PHP Syntax

1 
     

2> Comments in PHP

1 
     

3> Case Sensitivity

In PHP, all keywords (e.g. if, else, while, echo, etc.), classes, functions, and user-defined functions are NOT case-sensitive.

1 
     ";3 echo "Hello World!
";4 EcHo "Hello World!
";5 ?>

However; all variable names are case-sensitive.

1 
     ";4 echo "My house is " . $COLOR . "
";5 echo "My boat is " . $coLOR . "
";6 ?>

4> PHP Variables

Rules for PHP variables:

• A variable starts with the $ sign, followed by the name of the variable
• A variable name must start with a letter or the underscore character
• A variable name cannot start with a number
• A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
• Variable names are case-sensitive ($age and $AGE are two different variables)

PHP is a Loosely Typed Language

PHP Variables Scope

PHP has three different variable scopes:

• local
• global
• static

PHP also stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable.

1 
     

5> PHP echo and print Statements

echo and print are more or less the same. They are both used to output data to the screen.

The differences are small:

• echo has no return value while print has a return value of 1 so it can be used in expressions.
• echo can take multiple parameters (although such usage is rare) while print can take one argument.
• echo is marginally faster than print.

echo Display Text

1 
     PHP is Fun!";3 echo "Hello world!
";4 echo "I'm about to learn PHP!
";5 echo "This ", "string ", "was ", "made ", "with multiple parameters.";6 ?>

echo Display Variables

1 
     $txt1"; 8 echo "Study PHP at $txt2
"; 9 echo $x + $y;10 ?>

print Display Text

1 
     PHP is Fun!";3 print "Hello world!
";4 print "I'm about to learn PHP!";5 ?>

print Display Variables

1 
     $txt1"; 8 print "Study PHP at $txt2
"; 9 print $x + $y;10 ?>

6> PHP Data Types

Variables can store data of different types, and different data types can do different things.

PHP supports the following data types:

• String
• Integer
• Float (floating point numbers - also called double)
• Boolean
• Array
• Object
• NULL
• Resource

Example

1 
     

Object Example

1 
     model = "VW"; 5     } 6 } 7  8 // create an object 9 $herbie = new Car();10 11 // show object properties12 echo $herbie->model;13 ?>