24. September 2017 · Comments Off on How to find Created, Published and Modified Dates for a Web Page · Categories: Web · Tags:
Finding the created, published or last modified date for web pages isn’t as straightforward as it might appear. Although there are several ways to find the dates of web pages, none are 100% reliable, because regardless of the method used, no standard exists for dating web pages. The most authoritative way to find dates is from the page content itself, and even that has its shortcomings, since nothing requires dates to be accurate in the first place. In most cases, the best that can be achieved will be an approximation.

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Some of the methods that can be used to find created, published, or modified dates for web pages:

  1. Web page content
  2. HTTP Headers
  3. Browser Plugins
  4. Javascript in Address Bar
  5. The Wayback Machine
  6. Google Cache
  7. RSS Feed

1. Web Page Content (preferred method when possible)

Pages often have a first published, updated, or posted date somewhere on the page. As mentioned previously, although this is the most accurate method, it still has its problems. An author could leave the date out, or use a wrong date – either intentionally or unintentionally. Even so, obtaining dates from web page content is the most accurate and authoritative method.

2. HTTP Headers

The Last-Modified field is an optional response field that reflects the date the origin server believes that the resource was modified. Because it is an optional field, it may or may not exist. Also, because no standard exists as to what the Last-Modified date field means, it’s often inaccurate or incorrect since that field also reflects any alterations made to the page, such as user comments or any changes other than the content.

3. Browser Plugins

There are browser plugins that can read a web page’s Last-Modified date field, but this method is still subject to the problems described for HTTP Headers above.

4. Javascript in Address Bar

This is a quick and easy way to retrieve the date from the site’s Last-Modified date field in the HTTP Headers. To use it, just copy and paste the JavaScript string below to the address bar:

javascript:alert(document.lastModified)

Note: With dynamically generated content this will not work. Also, newer Internet browsers with an Omnibox require the user to manually type in javascript: even after they paste the entire string.

5. The Wayback Machine

The Way Back Machine was created by the nonprofit organization, the Internet Archive. It archives sites from the World Wide Web and other Internet information. There are a number of limitations to using this method including:

  • not all pages on a site may be┬áincluded
  • not all sites are included. Webmasters can request that they not be included
  • often it doesn’t include all changes made to web sites
  • it may not be up-to-date. It can take several months for pages to appear
  • user-defined dates cannot be specified, but only dates crawled by the Way Back Machine’s web crawler

6. Google Cache

Google Cache displays a web page when it was last crawled by Google. There are several problems with this method including:

  • there isn’t a way to know the last time a page was crawled
  • it isn’t possible to specify a date range of the cache
  • changes to web sites are not tracked

To use Google Cache, enter the following into your web browser’s address bar, changing the name at the end of the URL to the site in question:

http://webcache.googleusercontent.com/search?q=cache:http://www.NameOfWebsite.com

7. RSS Feed

Many, but not all, sites include a RSS feed. If so, the published date for the page may be contained within its XML file. RSS XML files could have any name, but often use names such as index.xml or feed.xml. If it exists, it may be possible to view the file in a web browser to find dates. For further information, see Opening XML Files with a Browser. A simpler and easier option is to view the RSS feed for the page using a RSS feed reader.

Conclusion

If possible, the most authoritative and reliable method for finding the created, published, or modified dates is from the web page content. If dates don’t exist in the content, one or a combination of the above methods can be used to obtain approximate dates.

References:

Determine last modified date of a web page – Computer Hope

How do I find out when a web page was written? – Ask Leo

How to find out when a web page was created or updated – Maxi-Pedia

How to Know When a Web Page was Last Modified? – Infopackets

 

 

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