php - preg_match problem -

i have written function:

public static function isdecimal($value, $places = 2)     {         if(preg_match("/^[0-9]+(\.[0-9]{".$places."})?$/", $value)) {             return true;         } else {             return false;         }     } 

which designed test whether value being entered number/decimal number. however, if enter number "23c.32" or "2b3.23" returns true. can point out fault lies in regex?

it works fine here. problem must somewhere near function call.