How to determine the date when a web page was updated?

Question

Browsers

When browsing websites frequently, particularly those related to programming, it is useful to know when a page was last modified. Are there plugins for browsers that will show this?

Answer 1

To do this, the server must correctly return Last modified, and now few people care about this (although all search engines strongly recommend it), because. content is almost everywhere dynamic. You can see what the server gave in Firefox by clicking on the icon in the address bar -> More information -> General tab -> Modified.

Answer 2

Considering the laxity of the writers and the desire to correct the dates for their tasks (imitation of the rapid development of the blog, editing the material after the comments), the most correct thing would be to estimate the dates of the comments (almost always the time is fixed). Otherwise, everything that was advised earlier, adjusted for the mess. :-)

Answer 3

There is a simple bookmarklet. Make a link out of it and drag it to your bookmarks bar.
javascript:alert(document.lastModified);
Of course, it only works if the server returns the correct modification date. And if he gives the wrong one, then nothing will help anyway.

Answer 4

There may be special plugins.
if not, this, then a reason to write.
ff+firebug + see headers.

Answer 5

Alternatively, the Sitemap protocol has a <lastmod> tag that shows (if updated regularly) the time the document was last modified.

Answer 6

In general, I also had an idea how to track the date of real page changes:
1) load the page (and save)
2) wait for some time T
3) reload
4) find the diff of two pages
5) if the size of the diff does not exceed some number of bytes D
5.1) then double the waiting time T; goto 2
5.2) otherwise commit the change.
Sometimes the diff is really small (for example, with a banner spinner or displaying the current exchange rate, weather, or, even worse, the current time).
In this case, for this page, you need to increase D.