Good morning, I am passing the validator of W3C, and I would like to correct this error.
Gcs
Error: Bad value expires for attribute http-equiv on element meta.
From line 18, column 1; to line 18, column 43
panish"/>↩<meta http-equiv="expires" content="never">↩<meta
The expires value is not allowed in HTML5 for the <meta> tag and the http-equiv attribute, here you can see the specification: link
The only values allowed are:
'content-language', 'content-type', 'default-style', 'refresh' and 'set-cookie'
The solution is to send the field in the headings, which is defined here: link
An example is:
Expires: Thu, 01 Dec 1994 16:00:00 GMT
According to the documentation to send "never" as the expiration date, a date should be sent approximately one year after the HTTP response was sent , it is also recommended NOT to send dates after one year in the future.
The allowed attributes for http-equiv are:
content-language
Content-Security-Policy
content-type
default-style
refresh
set-cookie
Source:
The case you are trying to use "expires" is a special case and converts to an HTTP header.
Extensions to the predefined set of policies may, under certain circumstances, be registered on the WHATWG Wiki PragmaExtensions page.
These extensions must use a name that is identical to an HTTP header registered in the Permanent Message Header Field Registry, and must have an identical behavior to the one described by that HTTP header.
According to the spec you must use one year after the date of the shipping and should always be a valid date RFC 1123 .
<meta http-equiv="expires" content="Mon, 29 Aug 2017 17:06:13 GMT">