how to substring in javascript but excluding symbols

I need to use (substring method) in my javascript web network project, but excluding (:) colon symbol, because it is hexa decimal ip address, and I don’t want to accept (:) colons as a string or lets say number in the substring, I want to ignore it, how to do that?

this is the example IPV6 in the input field:

2001:2eb8:0dc1:54ed:0000:0000:0000:0f31

after substring from 1 to 12:

001:2eb8:0d

as you can see it accepted colons also, but in fact, I need this result:

2001:2eb8:0dc1

so by excluding these two symbols, it would have gave me that result above, but I don’t know how.

please don’t close my question.