⌨️ JavaScript Key Code Finder

What is the JavaScript Keycode Finder?

Every time you press a key in a browser, the page can fire a KeyboardEvent. The two properties you actually want today are event.key and event.code. event.key is the logical value the key produces, so pressing the A key gives "a" (or "A" with Shift), and pressing Enter gives "Enter". event.code is the physical button on the keyboard regardless of layout or modifiers, so the same A key is always "KeyA" and the top-row number one is always "Digit1". Use event.key when you care about the character a user typed, and event.code when you care about the physical position, which is what you want for game controls like WASD that should work the same on any keyboard layout.

You will still see event.keyCode and event.which in older code and tutorials. These are numeric codes (for example 65 for the A key, 13 for Enter, 27 for Escape) and they are deprecated. They are kept here because plenty of existing code and many interview questions still reference them, and because reading the number can help you recognise a key quickly. For anything new, prefer event.key and event.code, which are readable strings and are not affected by the inconsistencies that plagued the old numeric codes across browsers.

The event also tells you the state of the modifier keys through the boolean flags event.ctrlKey, event.altKey, event.shiftKey and event.metaKey (the Windows key or the Command key on a Mac). A property called event.location distinguishes otherwise identical keys, so it can tell a left Shift from a right Shift, or the numpad Enter from the main Enter. Together these let you build precise shortcuts, for example only acting when event.ctrlKey is true and event.code is "KeyS" to catch Ctrl+S.

When to use it

• Finding the exact event.code string to test when wiring up a keyboard shortcut such as Ctrl+S or the arrow keys.
• Choosing physical key codes (KeyW, KeyA, KeyS, KeyD) for game movement so controls work across keyboard layouts.
• Debugging why a key handler does not fire by confirming what value the browser actually reports for that key.
• Teaching or learning the difference between event.key, event.code and the deprecated event.keyCode.
• Checking which modifier keys a browser registers, including the difference between left and right via event.location.

How to use the JavaScript Keycode Finder

1. Click the capture box so it has keyboard focus.
2. Press any key, or a key combination, on your keyboard.
3. Read off event.key, event.code, the legacy event.keyCode and event.which, the location and any modifiers held.
4. Copy the generated listener snippet to drop a ready-made check for that exact key into your code.

Formula & method

Worked examples

Common keys and the values a keydown event reports for each

Common mistakes to avoid

• Using the deprecated event.keyCode in new code. event.keyCode and event.which are deprecated and were inconsistent across browsers. For new code use event.key for the character or event.code for the physical key, both of which are readable strings.
• Confusing event.key with event.code. event.key changes with layout and Shift (so "a" becomes "A"), while event.code is the fixed physical key ("KeyA"). For shortcuts and game controls that must ignore layout, use event.code.
• Forgetting to preventDefault on browser shortcuts. Keys like Ctrl+S, Ctrl+P or F5 trigger built-in browser actions. If you handle them, call event.preventDefault() inside your check, and note the browser may intercept some combinations before your code runs.
• Comparing the case of event.key without thinking about Shift. Because event.key returns "A" when Shift is held but "a" otherwise, a strict comparison to one case can miss the key. Lowercase the value, or use event.code which does not change with Shift.

Glossary

KeyboardEvent

The event object a browser fires for keydown, keypress and keyup, carrying all the key and modifier details.

event.key

The logical value the key produces, such as "a", "A", "Enter" or "ArrowLeft". It changes with layout and modifiers.

event.code

The physical key on the keyboard, such as "KeyA" or "Digit1", independent of layout, Shift or the produced character.

event.keyCode

A deprecated numeric code for the key (for example 65 for A). Kept for legacy code but no longer recommended.

event.location

A number telling which copy of a key was pressed: 0 standard, 1 left, 2 right, 3 numeric keypad.

Modifier key

A key like Ctrl, Alt, Shift or Meta (Windows or Command) whose held state is exposed as a boolean flag on the event.

Frequently asked questions