Use of dot ( . ) after www. in the URL

问题:

I often visit a link! But i have no idea what dot (.) represents in the URL.
What is use of dot (.) in the URL?

回答1:

The dot (.) is the character that was defined to be the delimiter in domain names (see DNS).

It delimits the labels in a domain name.

The domain name www.google.com consists of three labels:

• com (aka. the top-level domain)
• google (aka. the second-level domain)
• www (aka. the third-level domain, or subdomain)

回答2:

The '.' is like a character which differentiates from the domains. like www.todaysfuture.in the '.' after www means the first domain is done. then it checks the next domain.

The best example is like your email ID first is the email-ID then is the '@' that means the account name is done then comes gmail/yahoo/wtvr then a '.' to finish the account type then '.' com or in depending on the account

回答3:

Web addresses, or Uniform Resource Locators, go backwards with more specific terms coming first (like real addresses).

So for www.google.com

• com is the top level domain - it might be a global domain like .com or a country code like .uk, and some top level domains have sub divisions like .gov.uk and .co.uk.

• google is the domain - this is the name you actually buy and route to your servers/services

• www subdomain - these are optional, and can be used to distinguish different services running on the same server, so www.google.com would serve web pages while ftp.google.com might be an FTP service.

Note that the subdomain is often optional - google.com and most other servers will assume www as the default service or infer it from the protocol (the http:// bit).