How can i trim text ?

[eluser]margsot[/eluser]
I would like to trim text of one field called description to 100 characters.

I tried to use this php code in my view file but doesnt work.

Code:

$max_length = 100;

if (strlen($s) > $max_length)
{
    $offset = ($max_length - 3) - strlen($s);
    $s = substr($s, 0, strrpos($s, ' ', $offset)) . '...';
}