Single-layer air coil in a screen (20th century retro script)

In accordance with the declaration that I am reproducing the content of the Fonar website in this section, I am posting, without any changes or modifications, a script that allows the calculation of the inductance of a single-layer coil in a screen. This script was created by modifying an applet I wrote back in the 1990s and added to the Fonar website in the early 21st century. From a modern JavaScript perspective, it contains many unused approaches, such as the use of the var keyword, etc. I believe that from a practical perspective, the advantages of this script are negligible. However, it may be interesting for someone who programs in JavaScript and would like to see what a script written a quarter of a century ago looks like.

I should note in advance that due to the program's age, you may encounter problems running it in some browsers. I don't experience any. I invite you to view, try, and analyze the code:

Inductance of a single-layer air coil in a screen