When trying to validate that a string is made up of alphabetic characters only, two possible regex solutions come to my mind.

The first one checks that every character in the string is alphanumeric:

```
/^[a-z]+$/

```

The second one tries to find a character somewhere in the string that is **not** alphanumeric:

```
/[^a-z]/

```

*(Yes, I could use character classes here.)*

Is there any significant performance difference for long strings?
(If anything, I'd guess the second variant is faster.)