Update value_default.php

[iamrobert]

Same issue PHP 8.1

$element = !strlen($v) ? false : @$elements[ $v ];

to

$element = ($v !== null && !strlen($v)) ? false : @$elements[ $v ];

If accepted - please do a find and replace for other fields like:

radio checkbox etc

[ggppdk]

Looks good, merging on code review