DOM event handler exceptions are swallowed, so later listeners and dispatchEvent() continue running. Uncaught errors still reach the browser log and window error event.

RubyMine Finder searches can return huge result sets; file masks, directory limits, regex, and other filters narrow matches and speed up locating the right code.

Rails default ETags often never repeat because rotating CSRF tokens and CSP nonces change response bytes, blocking cache hits and 304 responses.

GitHub Actions CI template for Rails apps with parallel RSpec, RuboCop, ESLint, license checks, security scanning, and merged coverage reports.

Chaining Capybara matchers with and retries the full expectation when one check fails, making multiple assertions more reliable on pages that change asynchronously.

Directory uploads are possible with <input type="file" webkitdirectory multiple>, letting users select a folder and its nested files instead of choosing individual files.

HTTP header values are limited to low-ASCII for safe transport; non-ASCII data such as Umlauts or emojis can be carried by JSON-escaping characters above 127.

Capybara can fail tests after all steps when the Rails server raises an error on session cleanup. Filtering known missing-file errors avoids false failures.

Content Security Policy schützt Webseiten vor XSS, indem der Browser erlaubte Quellen für Skripte, Styles, Bilder und Verbindungen streng einschränkt.

Selenium browser tests see real system time unless the client clock is patched; timemachine.js and Timecop keep browser time aligned, while TZ can align the process time zone.

Noneditable HTML form controls behave differently with disabled and readonly: submission, focus, and tab order change, and browser quirks can affect fieldset descendants.

Relative asset URLs can work in Rails development but break after assets:precompile, because files are merged into public/assets and fingerprinted.

Quick reference for native DOM methods and properties that replace many jQuery calls, helping you find equivalents without browsing Element interfaces.

Useful Chrome DevTools console tricks for editing pages, timing code, inspecting elements, and reusing previous results.

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

Desktop number fields accept scientific notation, arrow-key changes, wheel scrolling, and stray letters, causing accidental edits and validation errors.

Single-line text can overflow its container in Rails views; text-overflow: ellipsis and white-space: nowrap produce cleaner truncation in supported browsers.

Moving a Rails app from the Asset Pipeline to Webpacker requires inventorying bundled libraries, repackaging legacy assets, and adjusting deployment for pack-based assets.

Live CSS and JS reloading in Rails with esbuild is awkward because generated assets change on every build. A guard-livereload plus livereload-js setup can avoid full-page reloads for stylesheet changes.

Frequent deployments fill application servers with old releases, tmp files, and stale compiled assets. Capistrano can automate release and asset cleanup to prevent disk-space exhaustion.

Passive listeners let the browser keep scrolling responsive by not waiting for touch or wheel handlers that never cancel default behavior.

Capybara/Selenium tests involve a test process, a server thread and a browser process, so blocking, stale time, and uncommitted transactions can cause seemingly impossible failures.