input:
abcde fghijklmnopqrstuvwxyz ABCDE FGHIJKLMNOPQRSTUVWXYZ 1234567890 !@#$%^&*() `-=[]\;',./~_+{}|:"<>?

output:
abcde fghijklmnopqrstuvwxyz ABCDE FGHIJKLMNOPQRSTUVWXYZ 1234567890 !@#$%^&*() `-=[]\;',./~_+{}|:"<>?

source:
<?php

$string = <<<EOF
abcde fghijklmnopqrstuvwxyz
ABCDE FGHIJKLMNOPQRSTUVWXYZ
\n\t1234567890
!@#$%^&*()
`-=[]\;',./~_+{}|:"<>?
EOF;

//$string = "hello world";

$pattern = '/[^a-z0-9\[\]\!\@\#\$\%\^\&\*\.\(\)\\\{\}\;\:\'\"\,\<\>\?\-\_\=\+\`\~\n\t \/\|]/is';
$replacement = '';
$post_body = preg_replace($pattern, $replacement, $string);

echo <<<EOF

<b>
input:<br />
<textarea rows="6" cols="50">$string</textarea><br />
<br />
output:<br />
<textarea rows="6" cols="50">$post_body</textarea><br />
<br />
source:<br />
</b>
EOF;

show_source(__FILE__);

?>