diff --git a/contenttype.go b/contenttype.go
index ef00adb..535bbe8 100755
--- a/contenttype.go
+++ b/contenttype.go
@@ -82,7 +82,7 @@ func SetContentTypeIfMedia(w http.ResponseWriter, r *http.Request) {
 	case ".gz":
 		w.Header().Set("Content-Encoding", "gzip")
 		v = "application/gzip"
-		if path.Ext(r.URL.Path) == ".js.gz" {
+		if strings.HasSuffix(r.URL.Path, ".js.gz") {
 			v = "application/javascript"
 		}
 	case ".gif":