diff --git a/context.go b/context.go
index d0b4e87f..779484b1 100644
--- a/context.go
+++ b/context.go
@@ -159,16 +159,15 @@ func (c *Context) Error(err error) *Error {
 	if err == nil {
 		panic("err is nil")
 	}
-	var parsedError *Error
-	switch err.(type) {
-	case *Error:
-		parsedError = err.(*Error)
-	default:
+
+	parsedError, ok := err.(*Error)
+	if !ok {
 		parsedError = &Error{
 			Err:  err,
 			Type: ErrorTypePrivate,
 		}
 	}
+
 	c.Errors = append(c.Errors, parsedError)
 	return parsedError
 }
@@ -695,7 +694,12 @@ func (c *Context) SecureJSON(code int, obj interface{}) {
 // It add padding to response body to request data from a server residing in a different domain than the client.
 // It also sets the Content-Type as "application/javascript".
 func (c *Context) JSONP(code int, obj interface{}) {
-	c.Render(code, render.JsonpJSON{Callback: c.DefaultQuery("callback", ""), Data: obj})
+	callback := c.DefaultQuery("callback", "")
+	if callback == "" {
+		c.Render(code, render.JSON{Data: obj})
+	} else {
+		c.Render(code, render.JsonpJSON{Callback: callback, Data: obj})
+	}
 }
 
 // JSON serializes the given struct as JSON into the response body.
diff --git a/context_test.go b/context_test.go
index a592bf5f..86e958aa 100644
--- a/context_test.go
+++ b/context_test.go
@@ -597,6 +597,20 @@ func TestContextRenderJSONP(t *testing.T) {
 	assert.Equal(t, "application/javascript; charset=utf-8", w.HeaderMap.Get("Content-Type"))
 }
 
+// Tests that the response is serialized as JSONP
+// and Content-Type is set to application/json
+func TestContextRenderJSONPWithoutCallback(t *testing.T) {
+	w := httptest.NewRecorder()
+	c, _ := CreateTestContext(w)
+	c.Request, _ = http.NewRequest("GET", "http://example.com", nil)
+
+	c.JSONP(201, H{"foo": "bar"})
+
+	assert.Equal(t, 201, w.Code)
+	assert.Equal(t, "{\"foo\":\"bar\"}", w.Body.String())
+	assert.Equal(t, "application/json; charset=utf-8", w.HeaderMap.Get("Content-Type"))
+}
+
 // Tests that no JSON is rendered if code is 204
 func TestContextRenderNoContentJSON(t *testing.T) {
 	w := httptest.NewRecorder()
diff --git a/ginS/gins.go b/ginS/gins.go
index ee00b381..a7686f23 100644
--- a/ginS/gins.go
+++ b/ginS/gins.go
@@ -128,7 +128,7 @@ func Run(addr ...string) (err error) {
 // RunTLS : The router is attached to a http.Server and starts listening and serving HTTPS requests.
 // It is a shortcut for http.ListenAndServeTLS(addr, certFile, keyFile, router)
 // Note: this method will block the calling goroutine undefinitelly unless an error happens.
-func RunTLS(addr string, certFile string, keyFile string) (err error) {
+func RunTLS(addr, certFile, keyFile string) (err error) {
 	return engine().RunTLS(addr, certFile, keyFile)
 }