Fly.io summarizes how to load JavaScript without affecting the display speed of the page. Jul 24, 2018 09:00:00 ... it halts interpretation of html and executes JavaScript, ...

None of the above-the-fold content on your page could be rendered without waiting for the following resources to load. Try to defer or asynchronously load blocking resources, or inline the critical ...

HTML doesn't care when you define an element's attributes as long as you give them values somewhere. This means that you have the ability to create a text box element dynamically and set its ...