The HEAD requests the headers that would be returned if the HEAD request's URL was instead requested with the HTTP GET method. For example, if a URL might produce a large download, a HEAD request could read its Content-Length header to check the filesize without actually downloading the file.
Warning: A response to a HEAD method should not have a body. If it has one anyway, that body must be ignored: any representation headers that might describe the erroneous body are instead assumed to describe the response which a similar GET request would have received.
If the response to a HEAD request shows that a cached URL response is now outdated, the cached copy is invalidated even if no GET request was made.
| Request has body | No |
|---|---|
| Successful response has body | No |
| Safe | Yes |
| Idempotent | Yes |
| Cacheable | Yes |
| Allowed in HTML forms | No |