diff --git a/modules/problem.js b/modules/problem.js
index e558ba5..1aaa45d 100644
--- a/modules/problem.js
+++ b/modules/problem.js
@@ -499,6 +499,9 @@ app.post('/problem/:id/manage', app.multer.fields([{ name: 'testdata', maxCount:
     problem.file_io_output_name = req.body.file_io_output_name;
 
     if (req.body.type === 'interaction') {
+      if (!problem.file_io) {
+        throw new ErrorMessage('交互题目必须使用文件 IO。');
+      }
       throw new ErrorMessage('暂不支持该题目类型。');
     }
 
diff --git a/views/problem_manage.ejs b/views/problem_manage.ejs
index 2de676c..9be6ea0 100644
--- a/views/problem_manage.ejs
+++ b/views/problem_manage.ejs
@@ -55,7 +55,7 @@
             <div class="inline fields">
               <label>IO 方式</label>
               <div class="field">
-                <div class="ui radio checkbox">
+                <div class="ui radio checkbox" id="std-io-div">
                   <input name="io_method" value="std-io" id="std-io" type="radio" onclick="goDisable()">
                   <label for="std-io">标准 IO</label>
                 </div>
@@ -125,11 +125,16 @@ $(function () {
   $('a[data-tab="traditional"]').click(function () {
     $('input[name=type]').val('traditional');
     if ($('div[data-tab="interaction"]').attr('data-tab', 'traditional').length) $('a[data-tab="traditional"]').click();
+
+    $('#std-io')[0].disabled = false;
   });
 
   $('a[data-tab="interaction"]').click(function () {
     $('input[name=type]').val('interaction');
     if ($('div[data-tab="traditional"]').attr('data-tab', 'interaction').length) $('a[data-tab="interaction"]').click();
+
+    $('#std-io')[0].disabled = true;
+    $('#file-io').click();
   });
 
   $('a[data-tab="submit-answer"]').click(function () {