Question

I shall this very day, at Doctor’s feast,
My bounden service duly pay thee.
But one thing!—For insurance’ sake, I pray thee,
Grant me a line or two, at least.

Mephistopheles, in Goethe's Faust

Forms were introduced briefly in the previous chapter as a way to submit information provided by the user over HTTP. They were designed for a pre-JavaScript Web, assuming that interaction with the server always happens by navigating to a new page.

But their elements are part of the DOM like the rest of the page, and the DOM elements that represent form fields support a number of properties and events that are not present on other elements. These make it possible to inspect and control such input fields with JavaScript programs and do things such as adding functionality to a traditional form or using forms and fields as building blocks in a JavaScript application.

This is a book about getting computers to do what you want them to do. Computers are about as common as screwdrivers today, but they contain a lot more hidden complexity and thus are harder to operate and understand. To many, they remain alien, slightly threatening things.