Page date from CSS Selector
Updating out of date content and ensuring that content is being reviewed on a regular basis is an important element of website maintenance.
Focus on newly created pages might also be interesting for you as a web editor, or monitoring modified pages over the last week in an administrator role.
The Page date from CSS Selector rule in Policy enables you to set up policies relating to all of the scenarios above.
This rule can be set up to pick up dates provided in a structured way on a website.
To keep setup minimal only a fixed set of date formats are allowed, and only dates provided without context are valid (that is, dates in the middle of a sentence aren't supported).
Identifying dates on pages
Identifying the HTML element on the page containing the date is done using a CSS selector.
The following example illustrates a meta tag in the head-section of each page carrying the date of the last modification of the page:
<head>
<title>My page</title>
<meta name="Last-Modified" content="2015-09-24T19:12:22Z" />
<meta name="description" content="My important content is on this page" />
</head>
This date can be picked up by Policy using a CSS selector. The CSS selector to match the Last-Modified meta tag would be: meta[name='Last-Modified']
Policy will read the value of the “content” attribute, and use that as the date.
Supported date formats
Only three formats are supported: Variants of ISO 8601, RFCs 1123, 5322 and 2822 as well as Unix Epoch dates.
| Group | Formats | Examples | Notes |
|---|---|---|---|
| ISO 8601 |
yyyy-MM-dd yyyy-MM-ddTHH:mm:ssK yyyy-MM-ddTHH:mm:ss.FFFFFFFK |
2015-09-24
2015-09-24T19:12:22Z 2015-09-24T19:12:22.0000000Z |
Supports three granularities: Date, date with time, and date with time and fractions. The timezone identifier is Z for UTC, or can be provided as +01:00 or +0100. No timezone identifier is interpreted as UTC. |
| RFCs |
ddd, dd, MMM yyyy HH:mm:ss GMT ddd, dd, MMM yyyy HH:mm:ss K |
Mon, 15 Jun 2009 20:45:30 GMT Mon, 15 Jun 2009 20:45:30 +0100 |
Variants are commonly used for HTTP date headers, such as the Last-Modified header. Day and month names must be in English, as per the RFCs. No timezone identifier is interpreted as UTC. |
| Unix Epoch | A large whole number | 1443052852 |
The number of seconds since 1st of January 1970 (also known as the Unix Epoch). The date will be interpreted as UTC. |
We highly recommend using meta tags to carry dates. This following table shows the built-in date formats that will be accepted by Policy in a range of programming languages:
| Language/environment | Format strings | Documentation |
|---|---|---|
| .NET | O, o, R, r | Standard Date and Time Format Strings |
| RFCs | c, r | Date/Time Functions |
| Java | N/A | Java doesn't natively support ISO 8601, but the Joda-Time library does. Learn more about Custom Formatters. |
What is ISO 8601?
ISO 8601 is an international standard for writing dates and times. Due to different date formats in different countries, it is very easy to misinterpret dates.
e.g. 11/03/15 - could mean 11th March 2015 or 3rd November 2015.
In 1988, the ISO (International Organization for Standardization) set a Global standard numeric date format, which was recognized internationally as the agreed way to represent dates, i.e.:
- YYYY-MM-DD
- 11th March 2015: 2015-03-11
- 3rd November 2015: 2015-11-03
Want to learn more about CSS selectors?
Interested to learn more about CSS selectors?
Read our article CSS Selectors & Siteimprove Policy and try out the CSS Selector rule in your policies.