How To: Check When a Website Was Last Modified Using Alert

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Each article published publicly on the Internet has a date of publication and last update. In addition to these two dates, the search results also display an indexed date. Whether you are a webmaster or a user, you sometimes need one of these dates for different purposes, for example to quote or link your site or to check its content.

How can I find the most recent update date of a web page?

Use the JavaScript command to display the date of the last modification

To get the date of the last update of a page you are on, simply type the following command in the address bar of your browser and press Enter or select the Go button:


A JavaScript alert window opens indicating the date and time of the last modification of the page.

For Chrome browser users and others, if you cut the command and paste it into the address bar, note that the “javascript:” part will be removed. This does not mean that you cannot use the command. All you have to do is type this bit in the command in the address bar.

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Perform a Google search

  1. Open the web page for which you want the date of the last modification.
  2. Copy everything after the last slash.
  3. Paste what you have just copied into a Google search or the Omnibox at the top of your browser, then press Enter.
  4. At the top of your search results, you should see the date the page was last modified or updated.

Display of the date of the last modification using a plug-in or a web browser add-on

There are browser plugins that specify the date when a web page was last modified, but this method does not always work. This is done by analyzing the “Last modification” command in the web server header, but not all web servers will provide this information when you visit a page. At the time of writing, many browser plugins I’ve been looking for (at least for Firefox) that use this method seem to be broken – most likely for the reasons I just mentioned. Everyone is invited to get involved with a plugin they are using – if it is reliable.

Using Wayback Machine

Enter the page address in the Wayback Machine and look at the list of results. You can use the results to get a general idea of the content update, although most websites are not indexed regularly, so you cannot get an exact date; moreover, some websites are not indexed at all by the Wayback Machine for various reasons, ranging from the site owner to the exclusion request to how the site was created.


In practice, web pages are very often created dynamically from a content management system or other, and in this case, the last modified header usually displays a data buffer to create the response, which is usually very close to the time of the request. This means that the header is practically useless in such cases.

Even with a “static” page (the server simply takes a file that matches the request and sends it), the date of the last change usually only displays the last write access to the file on the server. This may be a time when the file was restored from a backup copy, or a time when the file was modified on the server without changing its content, or a time when it was uploaded to the server, possibly replacing an old identical copy. In these cases, assuming that the timestamp is technically correct, it indicates a time after which the page has not been modified (but not necessarily the time of the last modification).

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