Using rifm for masking time in HH:MM format

[R-Oscar]

Is it possible to mask time in HH:MM format using rifm?

I need to implement following behavior:

User Input	Mask result
39:60	_9:_0
21:00	21:00

I tried using a replace with regex of such kind
/(([012])|[3-9_])((?<=2)(([0-3])|[4-9])|([\d_]))(.)(([0-5])|[6-9_])([\d_])/;
But the problem is that Safari doesn't support positive lookbehind and throws an error

Is there any other way?