Regex not working

Question

Can anyone tell me why my regex is not working on my cfinput textbox please. I only want to allow a-z as available charactors to enter and the below code fails.
<cfinput type="text"
        id="surname"
        name="surname"
        class="txt"
        title="Surname"
        value="#presentsurname#"
        validate="regex"
        pattern="[a-z]"
        message="Please enter a valid Surname."
        maxlength="60" />
If i type in $$$ then the regex is flagged up and I get the error message displayed.
Although if I type in a$$, I get no error message.
Thanks,
G

Answer 1

Thanks for the quick replies guys, your really helpful and both regex examples you have given both work.
To cut a long story short I was give the following regex to use against my surname textbox, and I need to follow 'their' standards so I must use this pattern.
([A-Z'\-]*)|([A-Z'\-][A-Z '\-]*[A-Z'\-])
And this should only allow A-Z (in capitals) and any of the other special charactors that are mentioned in the regex....  Although this pattern is allowing me to enter A$$ and I do not understand why it is allowing the $ sign to be an enterable charactor when the dollar sign is not listed in the regex.