Use this function to get the ASCII character from its ASCII value. Values above 255 will “wrap around” to zero. This is similar to what we saw with count_chars().

It will also take a negative number and wrap around backwards.

$a = chr( 65 );   // A
$b = chr( 97 );   // a
$c = chr( 360 );  // g
$d = chr( -159 ); // a
See the manual entry for chr()