Allow only capital and small letters

Question

I would like to accept only small and capital letters from the user.

I tried the below code, it echoes the invalid character message but doesn\'t work. I mean it doe

Answer 1

use this , this is giving me correct answer

if(!preg_match ('/^([a-zA-Z]+)$/', $fname)){
    echo "Invalid characters";
}
else{
    echo "correct";
}