Regex for validating domain name
If called as a method, any additional options are ignored.This returns the untainted domain name if the given is a valid domain.The Top Level Domain is probably the easiest to match.It is minimum 2 letter word that has a dot "in front" of it.( but it is not necessarily there`.Let's construct a Reg Ex to match any of them, step by step.First we should define the different parts we want to match and what they can be made of. This Name can contain every letter defined in the Unicode spec (This includes Emojis, btw).This can be called as either a subroutine or a method.
The last character must not be a minus sign or period.This returns the untainted label if the given is a valid label.A domain label is simply a single piece of a domain or hostname.A dotted quad (such as 127.0.0.1) is not considered a domain and will return false. Per RFC 1035, this sub does accept a value ending in a single period (i.e. This is called an absolute domain name, and should be properly resolved by any DNS tool (tested with A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.).
Note that periods are only allowed when they serve to delimit components of "domain style names".Host software MUST handle host names of up to 63 characters and SHOULD handle host names of up to 255 characters.