diff --git a/internal/web/js.go b/internal/web/js.go
index ee33d14cf..b2ad3f2db 100644
--- a/internal/web/js.go
+++ b/internal/web/js.go
@@ -17,11 +17,16 @@
 package web
 
 import (
+	"runtime"
 	"strings"
 
 	"github.com/gopherjs/gopherwasm/js"
 )
 
+func IsGopherJS() bool {
+	return runtime.GOOS != "js"
+}
+
 func IsBrowser() bool {
 	return true
 }
diff --git a/internal/web/notjs.go b/internal/web/notjs.go
index 65fd6cd89..5e677d863 100644
--- a/internal/web/notjs.go
+++ b/internal/web/notjs.go
@@ -16,6 +16,10 @@
 
 package web
 
+func IsGopherJS() bool {
+	return false
+}
+
 func IsBrowser() bool {
 	return false
 }
diff --git a/run.go b/run.go
index 3663a3142..617ab9feb 100644
--- a/run.go
+++ b/run.go
@@ -20,6 +20,7 @@ import (
 
 	"github.com/hajimehoshi/ebiten/internal/clock"
 	"github.com/hajimehoshi/ebiten/internal/ui"
+	"github.com/hajimehoshi/ebiten/internal/web"
 )
 
 var _ = __EBITEN_REQUIRES_GO_VERSION_1_11_OR_LATER__
@@ -91,7 +92,10 @@ var theGraphicsContext atomic.Value
 
 func run(width, height int, scale float64, title string, g *graphicsContext, mainloop bool) error {
 	atomic.StoreInt32(&isRunning, 1)
-	defer atomic.StoreInt32(&isRunning, 0)
+	// On GopherJS, run returns immediately.
+	if !web.IsGopherJS() {
+		defer atomic.StoreInt32(&isRunning, 0)
+	}
 	if err := ui.Run(width, height, scale, title, g, mainloop); err != nil {
 		if err == ui.RegularTermination {
 			return nil