diff --git a/header.go b/header.go
index 94f0697..c661e45 100644
--- a/header.go
+++ b/header.go
@@ -17,7 +17,7 @@ func (hh *HttpHeader) MarshalJSON() ([]byte, error) {
 	return []byte(hh.String()), nil
 }
 
-const (
+var (
 	HeaderKeyAccessControlAllowOrigin   HttpHeader = "Access-Control-Allow-Origin"   // 标识允许哪个域的请求
 	HeaderKeyAccessControlAllowHeaders  HttpHeader = "Access-Control-Allow-Headers"  // 标识允许的请求header
 	HeaderKeyAccessControlAllowMethods  HttpHeader = "Access-Control-Allow-Methods"  // 标识允许的请求方法