Eloquent JavaScript, 2nd Edition

Chapter 18. Forms and Form Fields

“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 ...