Last-Modified
The Last-Modified
response HTTP header contains the date and time at which the origin server believes the resource was last modified. It is used as a validator to determine if a resource received or stored is the same. Less accurate than an ETag
header, it is a fallback mechanism. Conditional requests containing If-Modified-Since
or If-Unmodified-Since
headers make use of this field.
Syntax
Last-Modified: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
Directives
- <day-name>
- One of "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", or "Sun" (case-sensitive).
- <day>
- 2 digit day number, e.g. "04" or "23".
- <month>
- One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" (case sensitive).
- <year>
- 4 digit year number, e.g. "1990" or "2016".
- <hour>
- 2 digit hour number, e.g. "09" or "23".
- <minute>
- 2 digit minute number, e.g. "04" or "59".
- <second>
- 2 digit second number, e.g. "04" or "59".
GMT
-
Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local time.
Examples
Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT
Specifications
|
Desktop |
|
Chrome |
Edge |
Firefox |
Internet Explorer |
Opera |
Safari |
Basic support |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
|
Mobile |
|
Android webview |
Chrome for Android |
Edge Mobile |
Firefox for Android |
Opera for Android |
iOS Safari |
Samsung Internet |
Basic support |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
See also