diff --git a/js/OnlineIDE.js b/js/OnlineIDE.js
index 0c4a8ec..1df1b68 100644
--- a/js/OnlineIDE.js
+++ b/js/OnlineIDE.js
@@ -361,7 +361,10 @@ function onExecuteResult(obj) {
     const executeResultTitleEl = $("#executeResultTitle");
     const data = obj;
     var sytleTail = "未知格式";
-    if (data.result instanceof Object) {
+    if (data.result==undefined) {
+      styleTail = "Undefined";
+      data.result = "";
+    } else if (data.result instanceof Object) {
         sytleTail = "JSON格式";
         data.result =JSON.stringify(data.result);
     } else if (typeof data.result == 'string') {