Avoid uppercase input with jQuery Validation Engine

Question

Some users a writing their messages in uppercase only, and I want to avoid that with JQuery Validation Engine.

I have tried many many regex without any success. Here is the idea for a custom rule to avoid more than 10 uppercase characters:

uppercase: {
   regex: /^(![A-Z]{10})+$/,
   alertText: "* uppercase test alert"
},

I can't figure out what's wrong.

Wiktor Stribiżew · Accepted Answer · 2018-03-02 13:39:28Z

3

If you want to only allow strings with 10 and fewer uppercase letters, you may use

/^(?!(?:[^A-Z]*[A-Z]){11})/

The pattern matches any string that does not contain 11 or more ASCII uppercase letters (so, it may contain 0 to 10 ASCII uppercase letters).

Details

^ - start of string
(?!(?:[^A-Z]*[A-Z]){11}) - a negative lookahead that fails the match if, immediately to the right of the current position, there are
- (?:[^A-Z]*[A-Z]){11} - 11 occurrences of
  - [^A-Z]* - any 0+ chars other than uppercase ASCII letters
  - [A-Z] - an uppercase ASCII letter.

If you want to match a string that has no 10 uppercase ASCII letters on end:

/^(?!.*[A-Z]{11})/

Details

^ - start of the string
(?!.*[A-Z]{11}) - a negative lookahead that fails the math if there are 11 uppercase ASCII letters after any 0+ chars other than line break chars immediately the right of the current location.

answered Mar 2, 2018 at 13:34

Wiktor Stribiżew

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