(PHP 4, PHP 5, PHP 7)
Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask.
int strspn ( string $subject, string $mask [, int $start [, int $length ]] )
Finds the length of the initial segment of subject that contains only characters from mask.
If start and length are omitted, then all of subject will be examined. If they are included, then the effect will be