Merge branch 'cxt_course' of https://git.trustie.net/jacknudt/trustieforge into cxt_course

app/controllers/exercise_controller.rb

@@ -450,7 +450,7 @@ class ExerciseController < ApplicationController
         if params[:answer_text].nil? || params[:answer_text].blank?
           #用户提交空答案，视作不作答
           @percent = get_percent(@exercise,User.current)
-          render :json => {:text => ea.answer_text,:percent => format("%.2f", @percent)}
+          render :json => {:text => "",:percent => format("%.2f", @percent)}
         else
           #添加答案
           ea = ExerciseAnswer.new
@@ -476,7 +476,7 @@ class ExerciseController < ApplicationController
           # 用户提交空答案，视为删除答案
           if ea.delete
             @percent = get_percent(@exercise,User.current)
-            render :json => {:text => ea.answer_text,:percent => format("%.2f", @percent)}
+            render :json => {:text => "",:percent => format("%.2f", @percent)}
           else
             render :json => {:text => "failure"}
           end