diff --git a/README.md b/README.md
index 6f02361..df89b7f 100644
--- a/README.md
+++ b/README.md
@@ -9,21 +9,25 @@ Recover middleware for elton, it can get panic error to avoid application crash.
 package main
 
 import (
+	"errors"
+
 	"github.com/vicanso/elton"
 
 	recover "github.com/vicanso/elton-recover"
 )
 
 func main() {
-	d := elton.New()
+	e := elton.New()
 
-	d.Use(recover.New())
+	e.Use(recover.New())
 
-	d.GET("/", func(c *elton.Context) (err error) {
-		panic("abcd")
+	e.GET("/", func(c *elton.Context) (err error) {
+		panic(errors.New("abcd"))
 	})
 
-	d.ListenAndServe(":3000")
+	err := e.ListenAndServe(":3000")
+	if err != nil {
+		panic(err)
+	}
 }
-
 ```
\ No newline at end of file
diff --git a/example/main.go b/example/main.go
index 0359d52..299450b 100644
--- a/example/main.go
+++ b/example/main.go
@@ -1,21 +1,23 @@
 package main
 
 import (
+	"errors"
+
 	"github.com/vicanso/elton"
 
 	recover "github.com/vicanso/elton-recover"
 )
 
 func main() {
-	d := elton.New()
+	e := elton.New()
 
-	d.Use(recover.New())
+	e.Use(recover.New())
 
-	d.GET("/", func(c *elton.Context) (err error) {
-		panic("abcd")
+	e.GET("/", func(c *elton.Context) (err error) {
+		panic(errors.New("abcd"))
 	})
 
-	err := d.ListenAndServe(":3000")
+	err := e.ListenAndServe(":3000")
 	if err != nil {
 		panic(err)
 	}
diff --git a/go.mod b/go.mod
index 8bb4cfd..e7887a5 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,6 @@ go 1.12
 
 require (
 	github.com/stretchr/testify v1.4.0
-	github.com/vicanso/elton v0.2.2
+	github.com/vicanso/elton v0.2.3
 	github.com/vicanso/hes v0.2.1
 )
diff --git a/go.sum b/go.sum
index 5cd9e0b..be84897 100644
--- a/go.sum
+++ b/go.sum
@@ -8,8 +8,8 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/vicanso/elton v0.2.2 h1:MZ5nfJFKBWDWnFPO8wRyPat8kZz3KoNBY0scemo7RFQ=
-github.com/vicanso/elton v0.2.2/go.mod h1:QFZ+Un4LLBANtl0mExkqLD4uqw3JLA2ZCWUHaCsHOUg=
+github.com/vicanso/elton v0.2.3 h1:XQskGFtw/hhtNXRU7dLX0OFcpG64pK4PMXh9CVjHVbA=
+github.com/vicanso/elton v0.2.3/go.mod h1:QFZ+Un4LLBANtl0mExkqLD4uqw3JLA2ZCWUHaCsHOUg=
 github.com/vicanso/hes v0.2.1 h1:jRFEADmiQ30koVY/sKwlkhyXM5B3QbVVizLqrjNJgPw=
 github.com/vicanso/hes v0.2.1/go.mod h1:QcxOFmFfBQMhASTaLgnFayXYCgevdSeBVprt+o+3eKo=
 github.com/vicanso/intranet-ip v0.0.1 h1:cYS+mExFsKqewWSuHtFwAqw/CO66GsheB/P1BPmSTx0=
diff --git a/recover_test.go b/recover_test.go
index 640e318..bd37fca 100644
--- a/recover_test.go
+++ b/recover_test.go
@@ -15,9 +15,9 @@ func TestRecover(t *testing.T) {
 	t.Run("response text", func(t *testing.T) {
 		assert := assert.New(t)
 		var ctx *elton.Context
-		d := elton.New()
-		d.Use(New())
-		d.GET("/", func(c *elton.Context) error {
+		e := elton.New()
+		e.Use(New())
+		e.GET("/", func(c *elton.Context) error {
 			ctx = c
 			panic("abc")
 		})
@@ -34,11 +34,11 @@ func TestRecover(t *testing.T) {
 		}
 
 		catchError := false
-		d.OnError(func(_ *elton.Context, _ error) {
+		e.OnError(func(_ *elton.Context, _ error) {
 			catchError = true
 		})
 
-		d.ServeHTTP(resp, req)
+		e.ServeHTTP(resp, req)
 		assert.Equal(resp.Code, http.StatusInternalServerError)
 		assert.Equal(resp.Body.String(), "category=elton-recover, message=abc")
 		assert.True(ctx.Committed)
@@ -50,15 +50,15 @@ func TestRecover(t *testing.T) {
 
 	t.Run("response json", func(t *testing.T) {
 		assert := assert.New(t)
-		d := elton.New()
-		d.Use(New())
-		d.GET("/", func(c *elton.Context) error {
+		e := elton.New()
+		e.Use(New())
+		e.GET("/", func(c *elton.Context) error {
 			panic("abc")
 		})
 		req := httptest.NewRequest("GET", "https://aslant.site/", nil)
 		req.Header.Set("Accept", "application/json, text/plain, */*")
 		resp := httptest.NewRecorder()
-		d.ServeHTTP(resp, req)
+		e.ServeHTTP(resp, req)
 		assert.Equal(500, resp.Code)
 		assert.Equal(elton.MIMEApplicationJSON, resp.Header().Get(elton.HeaderContentType))
 		assert.NotEmpty(resp.Body.Bytes())