diff --git a/genkeys.go b/genkeys.go
index e8e655149..47f5e0486 100644
--- a/genkeys.go
+++ b/genkeys.go
@@ -34,7 +34,7 @@ import (
 
 var (
 	nameToGLFWKeys    map[string]glfw.Key
-	nameToJSKeyCodes  map[string][]string
+	nameToJSKeyCode   map[string]string
 	keyCodeToNameEdge map[int]string
 )
 
@@ -85,68 +85,68 @@ func init() {
 		"Menu":         glfw.KeyMenu,
 		"Last":         glfw.KeyLast,
 	}
-	nameToJSKeyCodes = map[string][]string{
-		"Comma":        {"Comma"},
-		"Period":       {"Period"},
-		"LeftAlt":      {"AltLeft"},
-		"RightAlt":     {"AltRight"},
-		"CapsLock":     {"CapsLock"},
-		"LeftControl":  {"ControlLeft"},
-		"RightControl": {"ControlRight"},
-		"LeftShift":    {"ShiftLeft"},
-		"RightShift":   {"ShiftRight"},
-		"Enter":        {"Enter"},
-		"Space":        {"Space"},
-		"Tab":          {"Tab"},
-		"Delete":       {"Delete"},
-		"End":          {"End"},
-		"Home":         {"Home"},
-		"Insert":       {"Insert"},
-		"PageDown":     {"PageDown"},
-		"PageUp":       {"PageUp"},
-		"Down":         {"ArrowDown"},
-		"Left":         {"ArrowLeft"},
-		"Right":        {"ArrowRight"},
-		"Up":           {"ArrowUp"},
-		"Escape":       {"Escape"},
-		"Backspace":    {"Backspace"},
-		"Apostrophe":   {"Quote"},
-		"Minus":        {"Minus"},
-		"Slash":        {"Slash"},
-		"Semicolon":    {"Semicolon"},
-		"Equal":        {"Equal"},
-		"LeftBracket":  {"BracketLeft"},
-		"Backslash":    {"Backslash"},
-		"RightBracket": {"BracketRight"},
-		"GraveAccent":  {"Backquote"},
-		"NumLock":      {"NumLock"},
-		"Pause":        {"Pause"},
-		"PrintScreen":  {"PrintScreen"},
-		"ScrollLock":   {"ScrollLock"},
-		"Menu":         {"ContextMenu"},
+	nameToJSKeyCode = map[string]string{
+		"Comma":        "Comma",
+		"Period":       "Period",
+		"LeftAlt":      "AltLeft",
+		"RightAlt":     "AltRight",
+		"CapsLock":     "CapsLock",
+		"LeftControl":  "ControlLeft",
+		"RightControl": "ControlRight",
+		"LeftShift":    "ShiftLeft",
+		"RightShift":   "ShiftRight",
+		"Enter":        "Enter",
+		"Space":        "Space",
+		"Tab":          "Tab",
+		"Delete":       "Delete",
+		"End":          "End",
+		"Home":         "Home",
+		"Insert":       "Insert",
+		"PageDown":     "PageDown",
+		"PageUp":       "PageUp",
+		"Down":         "ArrowDown",
+		"Left":         "ArrowLeft",
+		"Right":        "ArrowRight",
+		"Up":           "ArrowUp",
+		"Escape":       "Escape",
+		"Backspace":    "Backspace",
+		"Apostrophe":   "Quote",
+		"Minus":        "Minus",
+		"Slash":        "Slash",
+		"Semicolon":    "Semicolon",
+		"Equal":        "Equal",
+		"LeftBracket":  "BracketLeft",
+		"Backslash":    "Backslash",
+		"RightBracket": "BracketRight",
+		"GraveAccent":  "Backquote",
+		"NumLock":      "NumLock",
+		"Pause":        "Pause",
+		"PrintScreen":  "PrintScreen",
+		"ScrollLock":   "ScrollLock",
+		"Menu":         "ContextMenu",
 	}
 	// ASCII: 0 - 9
 	for c := '0'; c <= '9'; c++ {
 		nameToGLFWKeys[string(c)] = glfw.Key0 + glfw.Key(c) - '0'
-		nameToJSKeyCodes[string(c)] = []string{"Digit" + string(c)}
+		nameToJSKeyCode[string(c)] = "Digit" + string(c)
 	}
 	// ASCII: A - Z
 	for c := 'A'; c <= 'Z'; c++ {
 		nameToGLFWKeys[string(c)] = glfw.KeyA + glfw.Key(c) - 'A'
-		nameToJSKeyCodes[string(c)] = []string{"Key" + string(c)}
+		nameToJSKeyCode[string(c)] = "Key" + string(c)
 	}
 	// Function keys
 	for i := 1; i <= 12; i++ {
 		name := "F" + strconv.Itoa(i)
 		nameToGLFWKeys[name] = glfw.KeyF1 + glfw.Key(i) - 1
-		nameToJSKeyCodes[name] = []string{name}
+		nameToJSKeyCode[name] = name
 	}
 	// Numpad
 	// https://www.w3.org/TR/uievents-code/#key-numpad-section
 	for c := '0'; c <= '9'; c++ {
 		name := "KP" + string(c)
 		nameToGLFWKeys[name] = glfw.KeyKP0 + glfw.Key(c) - '0'
-		nameToJSKeyCodes[name] = []string{"Numpad" + string(c)}
+		nameToJSKeyCode[name] = "Numpad" + string(c)
 	}
 
 	nameToGLFWKeys["KPDecimal"] = glfw.KeyKPDecimal
@@ -157,13 +157,13 @@ func init() {
 	nameToGLFWKeys["KPEnter"] = glfw.KeyKPEnter
 	nameToGLFWKeys["KPEqual"] = glfw.KeyKPEqual
 
-	nameToJSKeyCodes["KPDecimal"] = []string{"NumpadDecimal"}
-	nameToJSKeyCodes["KPDivide"] = []string{"NumpadDivide"}
-	nameToJSKeyCodes["KPMultiply"] = []string{"NumpadMultiply"}
-	nameToJSKeyCodes["KPSubtract"] = []string{"NumpadSubtract"}
-	nameToJSKeyCodes["KPAdd"] = []string{"NumpadAdd"}
-	nameToJSKeyCodes["KPEnter"] = []string{"NumpadEnter"}
-	nameToJSKeyCodes["KPEqual"] = []string{"NumpadEqual"}
+	nameToJSKeyCode["KPDecimal"] = "NumpadDecimal"
+	nameToJSKeyCode["KPDivide"] = "NumpadDivide"
+	nameToJSKeyCode["KPMultiply"] = "NumpadMultiply"
+	nameToJSKeyCode["KPSubtract"] = "NumpadSubtract"
+	nameToJSKeyCode["KPAdd"] = "NumpadAdd"
+	nameToJSKeyCode["KPEnter"] = "NumpadEnter"
+	nameToJSKeyCode["KPEqual"] = "NumpadEqual"
 }
 
 func init() {
@@ -337,10 +337,8 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/driver"
 )
 
-var keyToCodes = map[driver.Key][]string{
-{{range $name, $codes := .NameToJSKeyCodes}}driver.Key{{$name}}: []string{
-{{range $code := $codes}}"{{$code}}",{{end}}
-},
+var keyToCode = map[driver.Key]string{
+{{range $name, $code := .NameToJSKeyCode}}driver.Key{{$name}}: {{$code | printf "%q"}},
 {{end}}
 }
 
@@ -456,7 +454,7 @@ func main() {
 	ebitenKeyNames := []string{}
 	ebitenKeyNamesWithoutMods := []string{}
 	driverKeyNames := []string{}
-	for name := range nameToJSKeyCodes {
+	for name := range nameToJSKeyCode {
 		driverKeyNames = append(driverKeyNames, name)
 		if !strings.HasSuffix(name, "Alt") && !strings.HasSuffix(name, "Control") && !strings.HasSuffix(name, "Shift") {
 			ebitenKeyNames = append(ebitenKeyNames, name)
@@ -519,7 +517,7 @@ func main() {
 			License                   string
 			DoNotEdit                 string
 			BuildTag                  string
-			NameToJSKeyCodes          map[string][]string
+			NameToJSKeyCode           map[string]string
 			KeyCodeToNameEdge         map[int]string
 			EbitenKeyNames            []string
 			EbitenKeyNamesWithoutMods []string
@@ -529,7 +527,7 @@ func main() {
 			License:                   license,
 			DoNotEdit:                 doNotEdit,
 			BuildTag:                  buildTag,
-			NameToJSKeyCodes:          nameToJSKeyCodes,
+			NameToJSKeyCode:           nameToJSKeyCode,
 			KeyCodeToNameEdge:         keyCodeToNameEdge,
 			EbitenKeyNames:            ebitenKeyNames,
 			EbitenKeyNamesWithoutMods: ebitenKeyNamesWithoutMods,
diff --git a/internal/uidriver/js/input.go b/internal/uidriver/js/input.go
index 248170c1f..f947c3d13 100644
--- a/internal/uidriver/js/input.go
+++ b/internal/uidriver/js/input.go
@@ -128,10 +128,8 @@ func (i *Input) ResetForFrame() {
 
 func (i *Input) IsKeyPressed(key driver.Key) bool {
 	if i.keyPressed != nil {
-		for _, c := range keyToCodes[key] {
-			if i.keyPressed[c] {
-				return true
-			}
+		if i.keyPressed[keyToCode[key]] {
+			return true
 		}
 	}
 	if i.keyPressedEdge != nil {
@@ -275,12 +273,12 @@ func (i *Input) Update(e js.Value) {
 			return
 		}
 		cs := c.String()
-		if cs == keyToCodes[driver.KeyUp][0] ||
-			cs == keyToCodes[driver.KeyDown][0] ||
-			cs == keyToCodes[driver.KeyLeft][0] ||
-			cs == keyToCodes[driver.KeyRight][0] ||
-			cs == keyToCodes[driver.KeyBackspace][0] ||
-			cs == keyToCodes[driver.KeyTab][0] {
+		if cs == keyToCode[driver.KeyUp] ||
+			cs == keyToCode[driver.KeyDown] ||
+			cs == keyToCode[driver.KeyLeft] ||
+			cs == keyToCode[driver.KeyRight] ||
+			cs == keyToCode[driver.KeyBackspace] ||
+			cs == keyToCode[driver.KeyTab] {
 			e.Call("preventDefault")
 		}
 		i.keyDown(cs)
diff --git a/internal/uidriver/js/keys.go b/internal/uidriver/js/keys.go
index 236dee5f3..e164d3ef3 100644
--- a/internal/uidriver/js/keys.go
+++ b/internal/uidriver/js/keys.go
@@ -22,316 +22,110 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/driver"
 )
 
-var keyToCodes = map[driver.Key][]string{
-	driver.Key0: {
-		"Digit0",
-	},
-	driver.Key1: {
-		"Digit1",
-	},
-	driver.Key2: {
-		"Digit2",
-	},
-	driver.Key3: {
-		"Digit3",
-	},
-	driver.Key4: {
-		"Digit4",
-	},
-	driver.Key5: {
-		"Digit5",
-	},
-	driver.Key6: {
-		"Digit6",
-	},
-	driver.Key7: {
-		"Digit7",
-	},
-	driver.Key8: {
-		"Digit8",
-	},
-	driver.Key9: {
-		"Digit9",
-	},
-	driver.KeyA: {
-		"KeyA",
-	},
-	driver.KeyApostrophe: {
-		"Quote",
-	},
-	driver.KeyB: {
-		"KeyB",
-	},
-	driver.KeyBackslash: {
-		"Backslash",
-	},
-	driver.KeyBackspace: {
-		"Backspace",
-	},
-	driver.KeyC: {
-		"KeyC",
-	},
-	driver.KeyCapsLock: {
-		"CapsLock",
-	},
-	driver.KeyComma: {
-		"Comma",
-	},
-	driver.KeyD: {
-		"KeyD",
-	},
-	driver.KeyDelete: {
-		"Delete",
-	},
-	driver.KeyDown: {
-		"ArrowDown",
-	},
-	driver.KeyE: {
-		"KeyE",
-	},
-	driver.KeyEnd: {
-		"End",
-	},
-	driver.KeyEnter: {
-		"Enter",
-	},
-	driver.KeyEqual: {
-		"Equal",
-	},
-	driver.KeyEscape: {
-		"Escape",
-	},
-	driver.KeyF: {
-		"KeyF",
-	},
-	driver.KeyF1: {
-		"F1",
-	},
-	driver.KeyF10: {
-		"F10",
-	},
-	driver.KeyF11: {
-		"F11",
-	},
-	driver.KeyF12: {
-		"F12",
-	},
-	driver.KeyF2: {
-		"F2",
-	},
-	driver.KeyF3: {
-		"F3",
-	},
-	driver.KeyF4: {
-		"F4",
-	},
-	driver.KeyF5: {
-		"F5",
-	},
-	driver.KeyF6: {
-		"F6",
-	},
-	driver.KeyF7: {
-		"F7",
-	},
-	driver.KeyF8: {
-		"F8",
-	},
-	driver.KeyF9: {
-		"F9",
-	},
-	driver.KeyG: {
-		"KeyG",
-	},
-	driver.KeyGraveAccent: {
-		"Backquote",
-	},
-	driver.KeyH: {
-		"KeyH",
-	},
-	driver.KeyHome: {
-		"Home",
-	},
-	driver.KeyI: {
-		"KeyI",
-	},
-	driver.KeyInsert: {
-		"Insert",
-	},
-	driver.KeyJ: {
-		"KeyJ",
-	},
-	driver.KeyK: {
-		"KeyK",
-	},
-	driver.KeyKP0: {
-		"Numpad0",
-	},
-	driver.KeyKP1: {
-		"Numpad1",
-	},
-	driver.KeyKP2: {
-		"Numpad2",
-	},
-	driver.KeyKP3: {
-		"Numpad3",
-	},
-	driver.KeyKP4: {
-		"Numpad4",
-	},
-	driver.KeyKP5: {
-		"Numpad5",
-	},
-	driver.KeyKP6: {
-		"Numpad6",
-	},
-	driver.KeyKP7: {
-		"Numpad7",
-	},
-	driver.KeyKP8: {
-		"Numpad8",
-	},
-	driver.KeyKP9: {
-		"Numpad9",
-	},
-	driver.KeyKPAdd: {
-		"NumpadAdd",
-	},
-	driver.KeyKPDecimal: {
-		"NumpadDecimal",
-	},
-	driver.KeyKPDivide: {
-		"NumpadDivide",
-	},
-	driver.KeyKPEnter: {
-		"NumpadEnter",
-	},
-	driver.KeyKPEqual: {
-		"NumpadEqual",
-	},
-	driver.KeyKPMultiply: {
-		"NumpadMultiply",
-	},
-	driver.KeyKPSubtract: {
-		"NumpadSubtract",
-	},
-	driver.KeyL: {
-		"KeyL",
-	},
-	driver.KeyLeft: {
-		"ArrowLeft",
-	},
-	driver.KeyLeftAlt: {
-		"AltLeft",
-	},
-	driver.KeyLeftBracket: {
-		"BracketLeft",
-	},
-	driver.KeyLeftControl: {
-		"ControlLeft",
-	},
-	driver.KeyLeftShift: {
-		"ShiftLeft",
-	},
-	driver.KeyM: {
-		"KeyM",
-	},
-	driver.KeyMenu: {
-		"ContextMenu",
-	},
-	driver.KeyMinus: {
-		"Minus",
-	},
-	driver.KeyN: {
-		"KeyN",
-	},
-	driver.KeyNumLock: {
-		"NumLock",
-	},
-	driver.KeyO: {
-		"KeyO",
-	},
-	driver.KeyP: {
-		"KeyP",
-	},
-	driver.KeyPageDown: {
-		"PageDown",
-	},
-	driver.KeyPageUp: {
-		"PageUp",
-	},
-	driver.KeyPause: {
-		"Pause",
-	},
-	driver.KeyPeriod: {
-		"Period",
-	},
-	driver.KeyPrintScreen: {
-		"PrintScreen",
-	},
-	driver.KeyQ: {
-		"KeyQ",
-	},
-	driver.KeyR: {
-		"KeyR",
-	},
-	driver.KeyRight: {
-		"ArrowRight",
-	},
-	driver.KeyRightAlt: {
-		"AltRight",
-	},
-	driver.KeyRightBracket: {
-		"BracketRight",
-	},
-	driver.KeyRightControl: {
-		"ControlRight",
-	},
-	driver.KeyRightShift: {
-		"ShiftRight",
-	},
-	driver.KeyS: {
-		"KeyS",
-	},
-	driver.KeyScrollLock: {
-		"ScrollLock",
-	},
-	driver.KeySemicolon: {
-		"Semicolon",
-	},
-	driver.KeySlash: {
-		"Slash",
-	},
-	driver.KeySpace: {
-		"Space",
-	},
-	driver.KeyT: {
-		"KeyT",
-	},
-	driver.KeyTab: {
-		"Tab",
-	},
-	driver.KeyU: {
-		"KeyU",
-	},
-	driver.KeyUp: {
-		"ArrowUp",
-	},
-	driver.KeyV: {
-		"KeyV",
-	},
-	driver.KeyW: {
-		"KeyW",
-	},
-	driver.KeyX: {
-		"KeyX",
-	},
-	driver.KeyY: {
-		"KeyY",
-	},
-	driver.KeyZ: {
-		"KeyZ",
-	},
+var keyToCode = map[driver.Key]string{
+	driver.Key0:            "Digit0",
+	driver.Key1:            "Digit1",
+	driver.Key2:            "Digit2",
+	driver.Key3:            "Digit3",
+	driver.Key4:            "Digit4",
+	driver.Key5:            "Digit5",
+	driver.Key6:            "Digit6",
+	driver.Key7:            "Digit7",
+	driver.Key8:            "Digit8",
+	driver.Key9:            "Digit9",
+	driver.KeyA:            "KeyA",
+	driver.KeyApostrophe:   "Quote",
+	driver.KeyB:            "KeyB",
+	driver.KeyBackslash:    "Backslash",
+	driver.KeyBackspace:    "Backspace",
+	driver.KeyC:            "KeyC",
+	driver.KeyCapsLock:     "CapsLock",
+	driver.KeyComma:        "Comma",
+	driver.KeyD:            "KeyD",
+	driver.KeyDelete:       "Delete",
+	driver.KeyDown:         "ArrowDown",
+	driver.KeyE:            "KeyE",
+	driver.KeyEnd:          "End",
+	driver.KeyEnter:        "Enter",
+	driver.KeyEqual:        "Equal",
+	driver.KeyEscape:       "Escape",
+	driver.KeyF:            "KeyF",
+	driver.KeyF1:           "F1",
+	driver.KeyF10:          "F10",
+	driver.KeyF11:          "F11",
+	driver.KeyF12:          "F12",
+	driver.KeyF2:           "F2",
+	driver.KeyF3:           "F3",
+	driver.KeyF4:           "F4",
+	driver.KeyF5:           "F5",
+	driver.KeyF6:           "F6",
+	driver.KeyF7:           "F7",
+	driver.KeyF8:           "F8",
+	driver.KeyF9:           "F9",
+	driver.KeyG:            "KeyG",
+	driver.KeyGraveAccent:  "Backquote",
+	driver.KeyH:            "KeyH",
+	driver.KeyHome:         "Home",
+	driver.KeyI:            "KeyI",
+	driver.KeyInsert:       "Insert",
+	driver.KeyJ:            "KeyJ",
+	driver.KeyK:            "KeyK",
+	driver.KeyKP0:          "Numpad0",
+	driver.KeyKP1:          "Numpad1",
+	driver.KeyKP2:          "Numpad2",
+	driver.KeyKP3:          "Numpad3",
+	driver.KeyKP4:          "Numpad4",
+	driver.KeyKP5:          "Numpad5",
+	driver.KeyKP6:          "Numpad6",
+	driver.KeyKP7:          "Numpad7",
+	driver.KeyKP8:          "Numpad8",
+	driver.KeyKP9:          "Numpad9",
+	driver.KeyKPAdd:        "NumpadAdd",
+	driver.KeyKPDecimal:    "NumpadDecimal",
+	driver.KeyKPDivide:     "NumpadDivide",
+	driver.KeyKPEnter:      "NumpadEnter",
+	driver.KeyKPEqual:      "NumpadEqual",
+	driver.KeyKPMultiply:   "NumpadMultiply",
+	driver.KeyKPSubtract:   "NumpadSubtract",
+	driver.KeyL:            "KeyL",
+	driver.KeyLeft:         "ArrowLeft",
+	driver.KeyLeftAlt:      "AltLeft",
+	driver.KeyLeftBracket:  "BracketLeft",
+	driver.KeyLeftControl:  "ControlLeft",
+	driver.KeyLeftShift:    "ShiftLeft",
+	driver.KeyM:            "KeyM",
+	driver.KeyMenu:         "ContextMenu",
+	driver.KeyMinus:        "Minus",
+	driver.KeyN:            "KeyN",
+	driver.KeyNumLock:      "NumLock",
+	driver.KeyO:            "KeyO",
+	driver.KeyP:            "KeyP",
+	driver.KeyPageDown:     "PageDown",
+	driver.KeyPageUp:       "PageUp",
+	driver.KeyPause:        "Pause",
+	driver.KeyPeriod:       "Period",
+	driver.KeyPrintScreen:  "PrintScreen",
+	driver.KeyQ:            "KeyQ",
+	driver.KeyR:            "KeyR",
+	driver.KeyRight:        "ArrowRight",
+	driver.KeyRightAlt:     "AltRight",
+	driver.KeyRightBracket: "BracketRight",
+	driver.KeyRightControl: "ControlRight",
+	driver.KeyRightShift:   "ShiftRight",
+	driver.KeyS:            "KeyS",
+	driver.KeyScrollLock:   "ScrollLock",
+	driver.KeySemicolon:    "Semicolon",
+	driver.KeySlash:        "Slash",
+	driver.KeySpace:        "Space",
+	driver.KeyT:            "KeyT",
+	driver.KeyTab:          "Tab",
+	driver.KeyU:            "KeyU",
+	driver.KeyUp:           "ArrowUp",
+	driver.KeyV:            "KeyV",
+	driver.KeyW:            "KeyW",
+	driver.KeyX:            "KeyX",
+	driver.KeyY:            "KeyY",
+	driver.KeyZ:            "KeyZ",
 }
 
 var keyCodeToKeyEdge = map[int]driver.Key{