PHP Comparison Operators

Fuzzy Equals:

$a == $b Equal TRUE if $a is equal to $b after type juggling.

Identical Equals:

$a === $b Identical TRUE if $a is equal to $b, and they are of the same type.

Not logic:

$a != $b Not equal TRUE if $a is not equal to $b after type juggling.
$a !== $b Not identical TRUE if $a is not equal to $b, or they are not of the same type.

Resources:

Comparison Operators PHP manual description and examples
PHP Arithmetic, Assignment, and Comparison Operator examples and descriptions from W3 Schools.