If you want to match all printable characters in the UTF-8 set (as indicated by your comment on Aug 21), you're going to have a hard time doing this yourself. JavaScript's native regexes have abysmal Unicode support. But you can use XRegExp with the regex ^P{C}*$
.
If you only want to match those few ASCII letters you mentioned in the edit to your post from Aug 22, then the regex is trivial:
/^[a-z0-9!"#$%&'()*+,./:;<=>?@[] ^_`{|}~-]*$/i
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