If you are citing something from a web page, it is always a good idea to make a copy of it. Maybe save it as a PDF for your files. The lifespan of a web page is surprising short. It can be changed or even deleted, leaving little evidence behind.

A better idea might be to save the web page at the date and time of access into the Wayback Machine. The page, and outlinks, can be captured and added to Internet Archive, providing a link to how it appeared at the time. There is the added benefit of being able to compare the page at a later date to see any changes.

Internet Archive is one of the largest digital libraries in the world. They began with the Wayback Machine but it is now just one of the ways that they are preserving our digital history and making knowledge accessible to everyone.