Web Database Applications with PHP & MySQL, 2nd Edition

<=> (NULL-safe equality comparison operator) 

<base> element (HTML) 

<pre> tags 

\ (backslash) 

    in regular expressions 

{} (braces) (regular expressions) 

[] (brackets)

    client side scripts and 

    in regular expressions 

. (dot operator) 

== (double-equal operator) 

$ (end anchor) (regular expressions) 

=> (equal-to or greater-than operator) 

== (equality operator)

    string comparisons and 

/* and */ (multi-line comments) 

// (one-line comments) 

# (one-line comments) 

=== (is-identical operator) 

!== (is-not-identical operator)) 

* (matching operator) (regular expressions) 

+ (matching operator) (regular expressions) 

? (matching operator) (regular expressions) 

% (modulo function) 

!= (not equals operator) 

^ (not operator) (regular expressions) 

<?php and ?> script tags 

^ (start anchor) (regular expressions) 

4/5 rounding rules