When a form is submitted to a PHP script, the information from that form is automatically made available to the script. There are many ways

Sometimes it is convenient to be able to have variable variable names. That is, a variable name which can be set and used dynamically. A

The scope of a variable is the context within which it is defined. For the most part all PHP variables only have a single scope.

<?php // Unset AND unreferenced (no use context) variable; outputs NULL var_dump($unset_var); // Boolean usage; outputs ‘false’ (See ternary operators for more on this syntax)

Variables in PHP are represented by a dollar sign followed by the name of the variable. The variable name is case-sensitive. Variable names follow the

The special NULL value represents a variable with no value. NULL is the only possible value of type NULL. Note: The null type was introduced

To create a new object, use the new statement to instantiate a class: <?php class foo { function do_foo() { echo «Doing foo.»; } }

An array in PHP is actually an ordered map. A map is a type that associates values to keys. This type is optimized for several

A string is series of characters, therefore, a character is the same as a byte. That is, there are exactly 256 different characters possible. This

Floating point numbers (also known as «floats», «doubles», or «real numbers») can be specified using any of the following syntaxes: <?php $a = 1.234; $b