I came across the someone's password validate code, I tried to understand this regex but I cannot.
/(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])[a-zA-Z0-9]{8,}/
I especially don't get the part
(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])
(?=) what is this for and why are there 3 groups of them prior to [a-zA-Z0-9]?
