Need regex for specific requirement

Hello,

Thanks for reply.

I have tried with regex of decimal digits, it is working fine for static regex.
but when I change regex dynamically it is not working.

like I pass 2 scale then regex must validate following number :
12.23, 12.2, 12

if 3 scale then it should validate 12, 23.1, 23.12, 24.123

In short I need to make regex dynamically for decimal digits

For the first one, try:

    ^\d+(\.\d+)?$

and, for the second one:

    ^(https?://)?www(\.\w+){2,3}$