Keyboard & Mouse Tester

This tool helps you test keyboards and mice, and monitor input events in real-time. It's especially useful for developers debugging event handling code, and users checking if their input devices work correctly.

Keyboard Testing

The visual keyboard shows which keys you're pressing in real-time. Test all keys including function keys, modifiers, and special keys. The key information panel shows technical details like key code and scan code.

Mouse Testing

Test all mouse buttons (left, middle, right, back, forward), scroll wheel, and track precise cursor coordinates. Note: Due to browser limitations, back/forward button events fire on release rather than press.

Event Log for Developers

The event log captures all keyboard and mouse events with precise timestamps. You can see the exact sequence of mousedown, mouseup, click events, or keydown, keypress, keyup sequences. Filter events by type and export logs for analysis.

Understanding Coordinate Systems

Mouse positions are reported in multiple coordinate systems:

• clientX/Y - Position relative to the browser viewport (visible area)
• pageX/Y - Position relative to the entire document (includes scroll offset)
• screenX/Y - Position relative to the monitor screen
• offsetX/Y - Position relative to the target element
• movementX/Y - Relative movement since last event (useful for drag operations)

Ghosting & N-Key Rollover

Ghosting occurs when some key combinations don't register on certain keyboards. This tool helps you detect how many keys your keyboard can handle simultaneously (N-key rollover). Gaming keyboards typically support full NKRO.

Double-Click Detection

Test double-clicks for ALL mouse buttons (left, middle, right, back, forward) with customizable delay threshold (100-2000ms). Helps detect faulty switches causing unintended double-clicks. Adjust the delay setting to match your clicking speed.

Tips

• Some keys like F1-F12 may be intercepted by the browser or OS. Try pressing Fn key if available.
• The event log is useful for debugging JavaScript input handling code.
• Use the coordinate systems panel to understand how different position values work.
• Export event logs to analyze input timing and event sequences.
• The visual keyboard supports both ANSI (US) and ISO (EU) layouts.