Browser laboratory

Explore what your browser exposes and changes

Run controlled checks for browser identity, navigation, file handling, permissions and DOM integrity. Results stay in this page unless a test explicitly opens a URL or creates a local download.

01
Passive inspection

Environment and rendering

See the browser, platform, screen and graphics information available to page scripts without requesting permission.

ID

Environment summary

High-level runtime and display facts.

NV

Navigator snapshot

Values exposed through the Navigator API.

GL

Graphics and screen

Viewport, pixel density and WebGL renderer.

PX

Resolution frame tests

Open a frame with exact target dimensions. All four orange edges are visible only when the available viewport can contain the selected resolution.

The test measures the page viewport, not the monitor's advertised resolution. Browser tabs, toolbars, zoom and operating-system scaling can reduce the usable area.

02
Active checks

Navigation and user interaction

Learn which navigation operations and input events are allowed in the current browser or controlled environment.

Navigation and tabs

Test tabs, popups, history and URL transitions.

Input event monitor

Inspect mouse, keyboard, wheel and context-menu events.

Focus here and test click, right click, double click, wheel, Ctrl combinations and function keys.
Focus the area before typing. Movement events appear in the console below.
03
File boundaries

Uploads and downloads

Verify how the browser exposes selected-file metadata and handles locally generated download targets.

Upload tests

Choose or drop files and inspect the metadata visible to the page.

Drop files here or use the selectors above

Download tests

Create browser-side files and try different delivery mechanisms.

04
Browser capabilities

Permissions and protected APIs

Query capability state without assuming access. Some checks may be limited by HTTPS, browser policy or user settings.

API

Permissions and APIs

Inspect permissions, media devices, WebRTC and storage estimates.

05
Capture conditions

State, scale and reproducibility

Inspect contextual facts that can change how a page is displayed, timestamped, stored or captured.

DPR

Scale, zoom and pixel density

Compare the CSS viewport, visual viewport, screen dimensions and device pixel ratio.

UTC

Date, time and locale

Record local time, UTC, timezone, languages and regional formatting at the same instant.

VIS

Visibility and focus log

Observe focus, blur and tab visibility changes while moving between windows or tabs.

DB

Persistence and isolation

Write, read and clear namespaced values in cookies, local storage and session storage.

CP

Clipboard access

Test browser-mediated clipboard read and write. Permission and a user gesture may be required.

FS

Fullscreen dimensions

Compare the viewport before and after entering fullscreen mode.

Fullscreen test areaPress Escape to leave fullscreen.
SHA

File metadata and SHA-256

Select a local file to inspect basic metadata and calculate its cryptographic digest in this browser.

NET

Network and security context

Inspect connection state, protocol, secure context, service workers and response headers visible to the page.

MS

Loading lifecycle

Review navigation timing, DOM readiness, load completion and resource counts.

PDF

Print and PDF output

Open the browser print dialog to inspect pagination or save the current diagnostic page as PDF.

06
Page integrity

DOM inspection and change detection

Compare the HTML delivered by the server with the live document after browser parsing, scripts and interactions.

</>

Runtime DOM snapshot

Export the current document, head, body and loaded resources.

Δ

Original versus runtime HTML

Find additions, removals and changes introduced after delivery.

Original HTML is fetched again from the current URL. Runtime HTML comes from document.documentElement.outerHTML.
StatusOriginalOriginal LineRuntimeRuntime Line

DOM mutation log

Observe changes made after the monitor starts.