page 1 - Very light in size with a basic form. Very little form validation and cookie setting JS code here. page 2 - Very high amount of JS code depending on cookies set and form fields on previous page. There can be a lot of user interaction. page 3 - Very high amount of JS code used to work with HTML and CSS.
Now, since page-1 is very light in size, I want to download some of the JS code used on page-2, when user lands on page-1. I want to put it in browser cache and use it when user reaches page-2. Page-2 has a lot of interaction, and user is expected to be on this page for some time. I want to use this idle internet connection time to download the JS code for page-3.