Interactive benchmarks comparing Bootstrap 5.3.8 JavaScript components against native browser API equivalents. Each benchmark measures initialization time, operation speed, memory usage, DOM mutations, and code size.
performance.memory API is Chrome-only.
Other metrics work across all modern browsers.
Bootstrap Collapse JS (270 lines, scrollHeight calc) vs native <details>/<summary> (zero JS).
50 items × 100 toggle cycles
Bootstrap Offcanvas JS (638 lines with utils) vs native <dialog> element.
500 open/close cycles
Bootstrap Dropdown JS (988 lines + Floating UI) vs native Popover API + CSS Anchor Positioning.
20 dropdowns × 100 cycles
Bootstrap Tooltip JS (745 lines + Floating UI) vs native Popover API.
200 tooltips, sequential trigger
Bootstrap Popover JS (111 lines + Tooltip parent) vs native Popover API.
100 popovers, sequential trigger
Bootstrap Toast JS (class toggler + timer + 41 KB infra) vs native Popover API (popover="manual").
20 toasts × 100 show/hide cycles
Bootstrap Accordion JS (Collapse + data-bs-parent + 41 KB infra) vs native <details name=""> exclusive accordion.
10 groups × 5 items × 100 switch cycles
Bootstrap Carousel JS (slide engine + touch/swipe + ~50 KB infra) vs native CSS scroll-snap (zero JS).
10 carousels × 5 slides × 100 slide cycles
Bootstrap Tab JS (panel switcher + ARIA + 43 KB infra) vs native <details name=""> exclusive accordion.
20 groups × 4 tabs × 100 switch cycles
Bootstrap ScrollSpy JS (config parser + event system + 44 KB infra wrapping IO) vs native IntersectionObserver (~15 lines).
20 containers × 10 sections × 50 scroll cycles
Bootstrap .was-validated / .is-invalid JS class toggling vs native :user-valid / :user-invalid (zero JS).
50 fields × 100 toggle cycles
Modern browser APIs that could replace Bootstrap’s JavaScript with zero JS — but aren’t used yet.
<button commandfor="dialog" command="showModal"> — toggle dialogs, popovers, and fullscreen via HTML attributes. Zero JS event listeners.
Replaces: data-bs-toggle + event handler infrastructure
Smooth animated transitions between DOM states with document.startViewTransition(). Works across same-document and cross-document navigations.
Replaces: manual JS animation in Tab, Carousel, page transitions
Tie CSS animations to scroll position with animation-timeline: scroll() / view(). No scroll event listeners or requestAnimationFrame.
Replaces: ScrollSpy scroll listeners + offset calculations
aria-busy Loading IndicatorSet aria-busy="true" on any HTML element to show a loading spinner via CSS. One native attribute — no custom classes, no JS. Fully accessible.
Replaces: JS spinner libraries, custom loading components
<select>Style native <select> dropdowns with CSS via appearance: base-select — custom options, icons, search. No JS dropdown reconstruction.
Replaces: JS-based custom select/dropdown components
Position tooltips, popovers, and dropdowns relative to a trigger element — no Floating UI or JS offset math needed.
Replaces: Floating UI in Dropdown, Tooltip, Popover
@starting-styleDefine starting values for CSS transitions when elements first appear — fade-in popovers, slide-in dialogs, animate from display:none. Zero animation JS.
Replaces: .fade + .show JS class toggling in Modal, Offcanvas, Toast
:has() CSS SelectorSelect parent elements based on their children — the “parent selector” CSS never had. Replaces JS DOM queries and class toggling.
Replaces: JS form validation, parent state toggling, layout detection
content-visibility: autoSkip rendering offscreen content until the user scrolls to it. Two CSS properties replace IntersectionObserver boilerplate entirely.
Replaces: IntersectionObserver (~50–100 lines), virtual scrolling libraries
A modern replacement for the History API — intercept, manage, and navigate SPA “pages” with a single event listener. No router library needed.
Replaces: History API pushState/popstate, SPA router libraries
Built-in HTML elements and CSS capabilities that improve performance and UX — no JavaScript required.
<picture>, srcset, and sizes — browser selects the optimal image for every device: resolution, viewport, and format. Zero JS.
Replaces: single <img src> + .img-fluid CSS-only scaling
Static analysis reports for the Bootstrap codebase.
Structural code pattern analysis using ast-grep — finds code patterns across the Bootstrap source.
JavaScript linting report — code quality, style, and potential issues found by ESLint.
CSS linting report — style issues, best practices, and potential problems found by Stylelint.
Copy/paste detection report — duplicated code blocks found across the Bootstrap source by jscpd.
Using Bootstrap 5.3.8 from jsDelivr CDN. Native API benchmarks use zero external JavaScript libraries.