I'm trying to write a regular expression that says first letter not to be uppercase and the rest 0-19 characters mixed case. This doesn't seem to do it.
!/^[A-Z][a-zA-Z]{0,19}$/ 
4 Answers
If you want the first letter lowercase, all the others lower-or-upper, you can do this:
/^[a-z][a-zA-Z]{0,19}$/ Notice that you cannot just say [^A-Z] because that would allow non-alpha characters through, like numbers.
Comments
One of many solutions is regex pattern
/^(?![A-Z])[a-zA-Z]{1,20}$/ ...which reads: one to twenty letters with no uppercase in first place
Comments
Change from:
!/^[A-Z][a-zA-Z]{0,19}$/ To:
/^[^A-Z][a-zA-Z]{0,19}$/ That should fix your problem.
2 Comments
jimeast
I tried that it didn't help but I think there might be something besides my regx that's messing up my validation my function function validate_forename(field) { if (field === "") { return "No Forename was entered.\n"; } else if (!/^[A-Z][a-zA-Z]{0,19}$/.test(field)) { return "forename must begin with capital and be between 1 and 20 letters" } return ""; }
Force444
Hmm. I'm not entirely sure what it could be the. Copy what you just wrote and put it as an edit to your question, so more people can see and help you out. Sorry.
Use [^A-Z] instead of [A-Z]
[^ ] is the opposite of [].It matches characters not contained within the brackests
So,it should be
/^[^A-Z][a-zA-Z]{0,19}$/ OR
simply use
/^[a-z][a-zA-Z]{0,19}$/ 
^inside your first[ ]or do[a-z]