The HEAD request may be executed before loading a large resource, to check resource size, validity, accessibility, and recent modification. (would be indicated by Content-Length/Last-Modified headers).
The HEAD requests cannot have a message body. But you still can send data to the server using the URL parameters. In this case, you are limited to the maximum size of the URL, which is about 2000 characters (it depends on the browser).
The HEAD method is defined as idempotent, which means that multiple identical HEAD requests should have the same effect as a single request.
The following example demonstrates sending a HEAD request to the server:
And the server response:
To read more about HTTP HEAD method please check RFC2616.