diff --git a/internal/ui/input.go b/internal/ui/input.go
index a4c951849..5c6f5422f 100644
--- a/internal/ui/input.go
+++ b/internal/ui/input.go
@@ -33,25 +33,6 @@ func CursorPosition() (x, y int) {
 	return current.input.cursorPosition()
 }
 
-type input struct {
-	keyPressed         [KeyMax]bool
-	mouseButtonPressed [MouseButtonMax]bool
-	cursorX            int
-	cursorY            int
-}
-
-func (i *input) isKeyPressed(key Key) bool {
-	return i.keyPressed[key]
-}
-
-func (i *input) isMouseButtonPressed(button MouseButton) bool {
-	return i.mouseButtonPressed[button]
-}
-
-func (i *input) cursorPosition() (x, y int) {
-	return i.cursorX, i.cursorY
-}
-
 var glfwKeyCodeToKey = map[glfw.Key]Key{
 	glfw.KeySpace: KeySpace,
 	glfw.KeyLeft:  KeyLeft,
diff --git a/internal/ui/input_js.go b/internal/ui/input_js.go
index af81cca86..7acce39ae 100644
--- a/internal/ui/input_js.go
+++ b/internal/ui/input_js.go
@@ -16,17 +16,34 @@
 
 package ui
 
+var keyCodeToKey = map[int]Key{
+	32: KeySpace,
+	37: KeyLeft,
+	39: KeyRight,
+	38: KeyUp,
+	40: KeyDown,
+}
+
+var currentInput input
+
 func IsKeyPressed(key Key) bool {
-	// TODO: Implement this.
-	return false
+	return currentInput.isKeyPressed(key)
 }
 
 func IsMouseButtonPressed(button MouseButton) bool {
-	// TODO: Implement this.
-	return false
+	return currentInput.isMouseButtonPressed(button)
 }
 
 func CursorPosition() (x, y int) {
-	// TODO: Implement this.
-	return 0, 0
+	return currentInput.cursorPosition()
+}
+
+func (i *input) keyDown(key int) {
+	k := keyCodeToKey[key]
+	i.keyPressed[k] = true
+}
+
+func (i *input) keyUp(key int) {
+	k := keyCodeToKey[key]
+	i.keyPressed[k] = false
 }
diff --git a/internal/ui/keys.go b/internal/ui/keys.go
index d7eb93bf7..ad157cade 100644
--- a/internal/ui/keys.go
+++ b/internal/ui/keys.go
@@ -33,3 +33,22 @@ const (
 	MouseButtonMiddle
 	MouseButtonMax
 )
+
+type input struct {
+	keyPressed         [KeyMax]bool
+	mouseButtonPressed [MouseButtonMax]bool
+	cursorX            int
+	cursorY            int
+}
+
+func (i *input) isKeyPressed(key Key) bool {
+	return i.keyPressed[key]
+}
+
+func (i *input) isMouseButtonPressed(button MouseButton) bool {
+	return i.mouseButtonPressed[button]
+}
+
+func (i *input) cursorPosition() (x, y int) {
+	return i.cursorX, i.cursorY
+}
diff --git a/internal/ui/ui_js.go b/internal/ui/ui_js.go
index bfe894d46..ad64f4b33 100644
--- a/internal/ui/ui_js.go
+++ b/internal/ui/ui_js.go
@@ -66,6 +66,21 @@ func init() {
 		panic(err)
 	}
 	context = opengl.NewContext(webglContext)
+
+	// Make the canvas focusable.
+	canvas.Call("setAttribute", "tabindex", 1)
+	canvas.Get("style").Set("outline", "none")
+
+	canvas.Set("onkeydown", func(e js.Object) {
+		defer e.Call("preventDefault")
+		code := e.Get("keyCode").Int()
+		currentInput.keyDown(code)
+	})
+	canvas.Set("onkeyup", func(e js.Object) {
+		defer e.Call("preventDefault")
+		code := e.Get("keyCode").Int()
+		currentInput.keyUp(code)
+	})
 }
 
 func Start(width, height, scale int, title string) (actualScale int, err error) {