und Php
$a and $b And true if both $a and $b are true.
$a or $b Or true if either $a or $b is true.
$a xor $b Xor true if either $a or $b is true, but not both.
! $a Not true if $a is not true.
$a && $b And true if both $a and $b are true.
$a || $b Or true if either $a or $b is true.
Worried Wallaby