diff --git a/audio/mp3/decode_js.go b/audio/mp3/decode_js.go
index d22a67672..c92d5e85e 100644
--- a/audio/mp3/decode_js.go
+++ b/audio/mp3/decode_js.go
@@ -159,21 +159,21 @@ func Decode(context *audio.Context, src audio.ReadSeekCloser) (*Stream, error) {
 	return s, nil
 }
 
-var offlineAudioContextClass = js.Null
+var offlineAudioContextClass = js.Null()
 
 func init() {
-	if klass := js.Global.Get("OfflineAudioContext"); klass != js.Undefined {
+	if klass := js.Global().Get("OfflineAudioContext"); klass != js.Undefined() {
 		offlineAudioContextClass = klass
 		return
 	}
-	if klass := js.Global.Get("webkitOfflineAudioContext"); klass != js.Undefined {
+	if klass := js.Global().Get("webkitOfflineAudioContext"); klass != js.Undefined() {
 		offlineAudioContextClass = klass
 		return
 	}
 }
 
 func decode(context *audio.Context, buf []byte, try int) (*Stream, error) {
-	if offlineAudioContextClass == js.Null {
+	if offlineAudioContextClass == js.Null() {
 		return nil, errors.New("audio/mp3: OfflineAudioContext is not available")
 	}
 
@@ -205,7 +205,7 @@ func decode(context *audio.Context, buf []byte, try int) (*Stream, error) {
 		}
 	}), js.NewCallback(func(args []js.Value) {
 		err := args[0]
-		if err != js.Null || err != js.Undefined {
+		if err != js.Null() || err != js.Undefined() {
 			ch <- fmt.Errorf("audio/mp3: decodeAudioData failed: %v", err)
 		} else {
 			// On Safari, error value might be null and it is needed to retry decoding
diff --git a/audio/mp3/float32_wasm.go b/audio/mp3/float32_wasm.go
index b68c89c63..d05d523f7 100644
--- a/audio/mp3/float32_wasm.go
+++ b/audio/mp3/float32_wasm.go
@@ -25,7 +25,7 @@ import (
 func float32ArrayToSlice(arr js.Value) []float32 {
 	bytes := make([]byte, arr.Length()*4)
 	buf := arr.Get("buffer").Call("slice", arr.Get("byteOffset"), arr.Get("byteOffset").Int()+arr.Get("byteLength").Int())
-	js.ValueOf(bytes).Call("set", js.Global.Get("Uint8Array").New(buf))
+	js.ValueOf(bytes).Call("set", js.Global().Get("Uint8Array").New(buf))
 
 	bh := (*reflect.SliceHeader)(unsafe.Pointer(&bytes))
 	var f []float32
diff --git a/ebitenutil/file_js.go b/ebitenutil/file_js.go
index bdb0b04c9..8e713290d 100644
--- a/ebitenutil/file_js.go
+++ b/ebitenutil/file_js.go
@@ -36,7 +36,7 @@ func OpenFile(path string) (ReadSeekCloser, error) {
 	var err error
 	var content js.Value
 	ch := make(chan struct{})
-	req := js.Global.Get("XMLHttpRequest").New()
+	req := js.Global().Get("XMLHttpRequest").New()
 	req.Call("open", "GET", path, true)
 	req.Set("responseType", "arraybuffer")
 	req.Call("addEventListener", "load", func() {
diff --git a/examples/contextlost/main.go b/examples/contextlost/main.go
index 945ed79f1..4ad15612c 100644
--- a/examples/contextlost/main.go
+++ b/examples/contextlost/main.go
@@ -44,16 +44,16 @@ var (
 )
 
 func update(screen *ebiten.Image) error {
-	if inpututil.IsKeyJustPressed(ebiten.KeySpace) && js.Global != js.Null {
-		doc := js.Global.Get("document")
+	if inpututil.IsKeyJustPressed(ebiten.KeySpace) && js.Global() != js.Null() {
+		doc := js.Global().Get("document")
 		canvas := doc.Call("getElementsByTagName", "canvas").Index(0)
 		context := canvas.Call("getContext", "webgl")
-		if context == js.Null {
+		if context == js.Null() {
 			context = canvas.Call("getContext", "experimental-webgl")
 		}
 		// Edge might not support the extension. See
 		// https://developer.mozilla.org/en-US/docs/Web/API/WEBGL_lose_context
-		if ext := context.Call("getExtension", "WEBGL_lose_context"); ext != js.Null {
+		if ext := context.Call("getExtension", "WEBGL_lose_context"); ext != js.Null() {
 			ext.Call("loseContext")
 			fmt.Println("Context Lost!")
 		} else {
diff --git a/internal/clock/now_js.go b/internal/clock/now_js.go
index be95c995b..4d2d29801 100644
--- a/internal/clock/now_js.go
+++ b/internal/clock/now_js.go
@@ -24,5 +24,5 @@ import (
 
 func now() int64 {
 	// time.Now() is not reliable until GopherJS supports performance.now().
-	return int64(js.Global.Get("performance").Call("now").Float() * float64(time.Millisecond))
+	return int64(js.Global().Get("performance").Call("now").Float() * float64(time.Millisecond))
 }
diff --git a/internal/devicescale/impl_js.go b/internal/devicescale/impl_js.go
index c0566b2e8..8305fcbed 100644
--- a/internal/devicescale/impl_js.go
+++ b/internal/devicescale/impl_js.go
@@ -21,7 +21,7 @@ import (
 )
 
 func impl() float64 {
-	ratio := js.Global.Get("window").Get("devicePixelRatio").Float()
+	ratio := js.Global().Get("window").Get("devicePixelRatio").Float()
 	if ratio == 0 {
 		ratio = 1
 	}
diff --git a/internal/input/input_js.go b/internal/input/input_js.go
index 3e2e1a15c..b2c46c685 100644
--- a/internal/input/input_js.go
+++ b/internal/input/input_js.go
@@ -143,8 +143,8 @@ func (i *Input) setMouseCursor(x, y int) {
 }
 
 func (i *Input) UpdateGamepads() {
-	nav := js.Global.Get("navigator")
-	if nav.Get("getGamepads") == js.Undefined {
+	nav := js.Global().Get("navigator")
+	if nav.Get("getGamepads") == js.Undefined() {
 		return
 	}
 	gamepads := nav.Call("getGamepads")
@@ -152,7 +152,7 @@ func (i *Input) UpdateGamepads() {
 	for id := 0; id < l; id++ {
 		i.gamepads[id].valid = false
 		gamepad := gamepads.Index(id)
-		if gamepad == js.Undefined || gamepad == js.Null {
+		if gamepad == js.Undefined() || gamepad == js.Null() {
 			continue
 		}
 		i.gamepads[id].valid = true
@@ -183,7 +183,7 @@ func (i *Input) UpdateGamepads() {
 
 func OnKeyDown(e js.Value) {
 	c := e.Get("code")
-	if c == js.Undefined {
+	if c == js.Undefined() {
 		code := e.Get("keyCode").Int()
 		if keyCodeToKeyEdge[code] == KeyUp ||
 			keyCodeToKeyEdge[code] == KeyDown ||
@@ -215,7 +215,7 @@ func OnKeyPress(e js.Value) {
 }
 
 func OnKeyUp(e js.Value) {
-	if e.Get("code") == js.Undefined {
+	if e.Get("code") == js.Undefined() {
 		// Assume that UA is Edge.
 		code := e.Get("keyCode").Int()
 		theInput.keyUpEdge(code)
diff --git a/internal/opengl/context_js.go b/internal/opengl/context_js.go
index 27e686e94..9610e224d 100644
--- a/internal/opengl/context_js.go
+++ b/internal/opengl/context_js.go
@@ -38,7 +38,7 @@ type (
 	}
 )
 
-var InvalidTexture = Texture(js.Null)
+var InvalidTexture = Texture(js.Null())
 
 func getProgramID(p Program) programID {
 	return p.id
@@ -69,7 +69,7 @@ var (
 
 func init() {
 	// Accessing the prototype is rquired on Safari.
-	c := js.Global.Get("WebGLRenderingContext").Get("prototype")
+	c := js.Global().Get("WebGLRenderingContext").Get("prototype")
 	VertexShader = ShaderType(c.Get("VERTEX_SHADER").Int())
 	FragmentShader = ShaderType(c.Get("FRAGMENT_SHADER").Int())
 	ArrayBuffer = BufferType(c.Get("ARRAY_BUFFER").Int())
@@ -116,19 +116,19 @@ type context struct {
 }
 
 func Init() error {
-	if js.Global.Get("WebGLRenderingContext") == js.Undefined {
+	if js.Global().Get("WebGLRenderingContext") == js.Undefined() {
 		return fmt.Errorf("opengl: WebGL is not supported")
 	}
 
 	// TODO: Define id?
-	canvas := js.Global.Get("document").Call("querySelector", "canvas")
-	attr := js.Global.Get("Object").New()
+	canvas := js.Global().Get("document").Call("querySelector", "canvas")
+	attr := js.Global().Get("Object").New()
 	attr.Set("alpha", true)
 	attr.Set("premultipliedAlpha", true)
 	gl := canvas.Call("getContext", "webgl", attr)
-	if gl == js.Null {
+	if gl == js.Null() {
 		gl = canvas.Call("getContext", "experimental-webgl", attr)
-		if gl == js.Null {
+		if gl == js.Null() {
 			return fmt.Errorf("opengl: getContext failed")
 		}
 	}
@@ -138,9 +138,9 @@ func Init() error {
 	// Getting an extension might fail after the context is lost, so
 	// it is required to get the extension here.
 	c.loseContext = gl.Call("getExtension", "WEBGL_lose_context")
-	if c.loseContext != js.Null {
+	if c.loseContext != js.Null() {
 		// This testing function name is temporary.
-		js.Global.Set("_ebiten_loseContextForTesting", js.NewCallback(func([]js.Value) {
+		js.Global().Set("_ebiten_loseContextForTesting", js.NewCallback(func([]js.Value) {
 			c.loseContext.Call("loseContext")
 		}))
 	}
@@ -150,8 +150,8 @@ func Init() error {
 
 func (c *Context) Reset() error {
 	c.locationCache = newLocationCache()
-	c.lastTexture = Texture(js.Null)
-	c.lastFramebuffer = Framebuffer(js.Null)
+	c.lastTexture = Texture(js.Null())
+	c.lastFramebuffer = Framebuffer(js.Null())
 	c.lastViewportWidth = 0
 	c.lastViewportHeight = 0
 	c.lastCompositeMode = CompositeModeUnknown
@@ -176,8 +176,8 @@ func (c *Context) BlendFunc(mode CompositeMode) {
 func (c *Context) NewTexture(width, height int) (Texture, error) {
 	gl := c.gl
 	t := gl.Call("createTexture")
-	if t == js.Null {
-		return Texture(js.Null), errors.New("opengl: glGenTexture failed")
+	if t == js.Null() {
+		return Texture(js.Null()), errors.New("opengl: glGenTexture failed")
 	}
 	gl.Call("pixelStorei", unpackAlignment, 4)
 	c.BindTexture(Texture(t))
@@ -224,7 +224,7 @@ func (c *Context) DeleteTexture(t Texture) {
 		return
 	}
 	if c.lastTexture == t {
-		c.lastTexture = Texture(js.Null)
+		c.lastTexture = Texture(js.Null())
 	}
 	gl.Call("deleteTexture", js.Value(t))
 }
@@ -249,7 +249,7 @@ func (c *Context) NewFramebuffer(t Texture) (Framebuffer, error) {
 
 	gl.Call("framebufferTexture2D", framebuffer, colorAttachment0, texture2d, js.Value(t), 0)
 	if s := gl.Call("checkFramebufferStatus", framebuffer); s.Int() != framebufferComplete.Int() {
-		return Framebuffer(js.Null), errors.New(fmt.Sprintf("opengl: creating framebuffer failed: %d", s.Int()))
+		return Framebuffer(js.Null()), errors.New(fmt.Sprintf("opengl: creating framebuffer failed: %d", s.Int()))
 	}
 
 	return Framebuffer(f), nil
@@ -269,7 +269,7 @@ func (c *Context) DeleteFramebuffer(f Framebuffer) {
 	// will be a default framebuffer.
 	// https://www.khronos.org/opengles/sdk/docs/man/xhtml/glDeleteFramebuffers.xml
 	if c.lastFramebuffer == f {
-		c.lastFramebuffer = Framebuffer(js.Null)
+		c.lastFramebuffer = Framebuffer(js.Null())
 		c.lastViewportWidth = 0
 		c.lastViewportHeight = 0
 	}
@@ -279,8 +279,8 @@ func (c *Context) DeleteFramebuffer(f Framebuffer) {
 func (c *Context) NewShader(shaderType ShaderType, source string) (Shader, error) {
 	gl := c.gl
 	s := gl.Call("createShader", int(shaderType))
-	if s == js.Null {
-		return Shader(js.Null), fmt.Errorf("opengl: glCreateShader failed: shader type: %d", shaderType)
+	if s == js.Null() {
+		return Shader(js.Null()), fmt.Errorf("opengl: glCreateShader failed: shader type: %d", shaderType)
 	}
 
 	gl.Call("shaderSource", js.Value(s), source)
@@ -288,7 +288,7 @@ func (c *Context) NewShader(shaderType ShaderType, source string) (Shader, error
 
 	if !gl.Call("getShaderParameter", js.Value(s), compileStatus).Bool() {
 		log := gl.Call("getShaderInfoLog", js.Value(s))
-		return Shader(js.Null), fmt.Errorf("opengl: shader compile failed: %s", log)
+		return Shader(js.Null()), fmt.Errorf("opengl: shader compile failed: %s", log)
 	}
 	return Shader(s), nil
 }
@@ -301,7 +301,7 @@ func (c *Context) DeleteShader(s Shader) {
 func (c *Context) NewProgram(shaders []Shader) (Program, error) {
 	gl := c.gl
 	v := gl.Call("createProgram")
-	if v == js.Null {
+	if v == js.Null() {
 		return Program{}, errors.New("opengl: glCreateProgram failed")
 	}
 
@@ -352,7 +352,7 @@ func (c *Context) UniformFloat(p Program, location string, v float32) {
 }
 
 var (
-	float32Array = js.Global.Get("Float32Array")
+	float32Array = js.Global().Get("Float32Array")
 )
 
 func (c *Context) UniformFloats(p Program, location string, v []float32) {
@@ -450,7 +450,7 @@ func (c *Context) IsContextLost() bool {
 }
 
 func (c *Context) RestoreContext() {
-	if c.loseContext != js.Null {
+	if c.loseContext != js.Null() {
 		c.loseContext.Call("restoreContext")
 	}
 }
diff --git a/internal/ui/ui_js.go b/internal/ui/ui_js.go
index 5c16f1050..4ee26ff20 100644
--- a/internal/ui/ui_js.go
+++ b/internal/ui/ui_js.go
@@ -49,8 +49,8 @@ var currentUI = &userInterface{
 }
 
 var (
-	window                = js.Global.Get("window")
-	document              = js.Global.Get("document")
+	window                = js.Global().Get("window")
+	document              = js.Global().Get("document")
 	requestAnimationFrame = window.Get("requestAnimationFrame")
 )
 
@@ -226,7 +226,7 @@ func (u *userInterface) loop(g GraphicsContext) error {
 }
 
 func init() {
-	if document.Get("body") == js.Null {
+	if document.Get("body") == js.Null() {
 		ch := make(chan struct{})
 		window.Call("addEventListener", "load", js.NewCallback(func([]js.Value) {
 			close(ch)
diff --git a/internal/web/js.go b/internal/web/js.go
index feccb1f9c..ee33d14cf 100644
--- a/internal/web/js.go
+++ b/internal/web/js.go
@@ -27,7 +27,7 @@ func IsBrowser() bool {
 }
 
 func IsIOSSafari() bool {
-	ua := js.Global.Get("navigator").Get("userAgent").String()
+	ua := js.Global().Get("navigator").Get("userAgent").String()
 	if !strings.Contains(ua, "iPhone") {
 		return false
 	}
@@ -35,7 +35,7 @@ func IsIOSSafari() bool {
 }
 
 func IsAndroidChrome() bool {
-	ua := js.Global.Get("navigator").Get("userAgent").String()
+	ua := js.Global().Get("navigator").Get("userAgent").String()
 	if !strings.Contains(ua, "Android") {
 		return false
 	}