Rails 3.1 adds jQuery by default, streaming responses, role-based attr_accessible, prepared statements, and simpler migrations.

jQuery.spritely is a jQuery plugin created by Artlogic for creating dynamic character and background animation in pure HTML and JavaScript. It's a simple, light-weight plugin with a few simple methods for creating animated sprites such as the birds you see on this page, and dynamic scrolling backgrounds.

JavaScript value checks are inconsistent across primitives, objects, arrays, null, undefined, and NaN; the right test depends on whether you need type, instance, or property presence.

Use one(...) for handlers that should fire a single time; it accepts the same arguments as on(...) and removes itself after the first event.

Show or hide page sections based on form choices, including radio buttons, without intrusive scripting.

Tag clouds can be rendered and animated on an HTML5 canvas with TagCanvas, enabling interactive visualizations instead of plain text lists.

Jasmine DOM testing is easier with matchers like toBeVisible() and toHaveCss(css), plus fixture loading for temporary HTML setup and cleanup.

Responsive JavaScript lightbox for single images and galleries, with optional animations and straightforward setup.

jQuery plugin for packing page content into a dynamic, responsive layout that uses screen space efficiently.

BigVideo.js adds fit-to-fill background video or image playback for websites, with support for silent ambient loops and video playlists when autoplay is unavailable.

Attaching one listener to many elements can slow the browser; delegating to document reduces setup cost and suits low-frequency events like click.

We can now plug into every facet of the Rails jQuery UJS adapter, binding to custom events, and even customizing internal functions, without hacking or monkey-patching the rails.js file itself.

Fast web apps avoid unnecessary database work, oversized assets, and heavy client-side rendering, while measuring bottlenecks before optimizing caches, scripts, images, or page delivery.

Efficient ways to create DOM test fixtures for Jasmine, from HTML parsing and selector helpers to innerHTML, with readable structure and direct element references.

Rails 2.3.x upgrades fix security vulnerabilities and API changes across patch levels, with extra CSRF, XSS, and JSON gem updates needed on some releases.

String helper extensions for Underscore.js add convenient text utilities to JavaScript projects.

jqueryElement.is(':checked')

jsPlumb can visually connect elements together with curved (or straight) lines. The demo has examples of Bezier curves and straight lines.

toBe only checks reference identity; toEqual handles arrays, objects, dates, regular expressions, NaN, exceptions, and custom equality testers.

Capybara can locate DOM nodes by text content using text: with a selector or regular expression, avoiding unsupported CSS string-matching selectors.