PHP is loosely typed, meaning that it will implicitly change the type of a variable as needed, depending on the operation being performed on its value. This contrasts with strongly typed languages, like C and Java, where variables can only contain one type of data throughout their existence. Must be named using only letters, numbers and underscore. Must start with a letter or an underscore.
<php $name = 'valid'; // Valid name $_name = 'valid'; // Valid name $1name = 'invalid'; // Invalid name, starts with a numberAre one of only two identifier types in PHP that are case-sensitive (the other is constants)
<?php error_reporting(E_ALL); $Name = "John"; echo $name; // Notice: Undefined variable: name