Input field validations

Hi Experts,

I have a scenario, wherein, i need to fetch the input from the user using input field. The input field should be of 3 character length and the first character should be + or - and the last two digits should be numeric. eg. +12 or -45.

So, what should be the validations, to be done on that input field. If he gives the input in some other combination like 1 or ++2, error message should be populated. Please, send me the appropriate code.

Thanks & Regards,

Akshay.