HowardGriffin.org
A digital clock is a fairly straight forward application. The only whistles and bells are the ability to change size, to turn on and off the seconds, and switch to a 24 hour (military) format. All of that can be set via defaults or changed while the clock is running.
Just run the digital clock here
Or you can "right click" the above link and save the target locally. Then double click the downloaded file to run it in your favorite browser.
That's all there is, no installation needed.
An analog clock is quite a diferent story. The absolute nicest sample I've found is located here: https://codepen.io/rodnylobos/pen/KoJxq. It did require subdirectories and include files, both local and from the internet. It did not run without an internet connection, and sizing was difficult. So I didn't use it.
This internet requirement didn't suit our needs, so I modified and enhanced an example from w3schools.
Just run the analog clock here
Or you can "right click" the above link and save the target locally. Then double click the downloaded file to run it in your favorite browser.
That's all there is, no installation needed.
Oh, by the way. The Analog Clock does require html5.
The vast majority of browsers now support html5.