How to Add Scripts
The <scripts> element is used to embed script or reference to an executable script within an HTML document. Scripts are usually nested within the <head> element to ensure that the script is ready to run when it is called. However, there is no restriction, and the script could be placed anywhere in the document.
If you need the same scripts to be available for many web pages, then you should place scripts into a separate file, then call it from HTML document.
How to Trigger Scripts
You can specify whether to make a script run automatically (as soon as the page loads), or after the user has done something (like hovering over or clicking a link). If you want the script to run if the user performs any action (called event) then you should use event handlers to let the browser know, which event is responsible for triggering certain script.
Event handlers are specified as attributes within the HTML tag.
The <noscript> element