Question

I was wondering how can I limit a users input like HTML maxlength attribute but with PHP, example would be nice? Is MySQL varchar(255) one way to limit a users character input? What are the cons of just counting on MySQL to do this?

Answer 1

Have you taken a look at strlen?

$input = $_GET['input'];
if ( strlen($input) > 255 ){
    throw new Exception('Cannot have input exceeding 255 characters');
}

The main issues of counting on MySQL to truncate the length of a string is the lack of error handling. If users input has been truncated to a length they probably don’t intend it to be and it would (probably) be better to display an error page.