How to prevent a User from entering -ive number

Thx for help in advance…On LN Client I have a number field on a form. I don’t want that the user should input any negative number in that field. How should i prevent the user from entering any negative number.Pls help

Subject: How to prevent a User from entering -ive number

please check if the value is less than zero then give them a alert msg . for more call me on ajitnarayan123@gmail.com

Subject: RE: How to prevent a User from entering -ive number

Keep all of the discussion here in the forum, where it can be of use to everybody.

Ajit Narayan: you have been requested to stop soliciting offline conversations here many times before. You are hardly an expert – if you want to make a reputation for yourself, try offering useful and relevant responses in public.

Subject: -

Subject: How to prevent a User from entering -ive number

Input validation:@if(@ThisValue < 0; @Failure(“FieldNameLabel: Cannot have a negative value.”); @Success);