选择框默认显示文字类似于“请选择发布作业的课程”，点击即弹出供选择的课程列表，课程名称后还需要显示开课学期

app/helpers/users_helper.rb

@@ -546,7 +546,7 @@ module UsersHelper
     type = []
     user.courses.select{|c| user.allowed_to?(:as_teacher,c)}.each do |course|
       option = []
-      option << course.name
+      option << course.name+"（"+course.time.to_s+course.term+"）"
       option << course.id
       type << option
     end

app/views/users/_user_homework_form.html.erb

@@ -74,7 +74,11 @@
 </div>
   </div>
 <div class="cl"></div>
-
+<script type="text/javascript">
+    $(function (){
+        $("#course_id").append("<option value='-1'hidden selected>请选择发布作业的课程</option>");
+    });
+</script>
 
 <script id="t:test-answer-list" type="text/html">
   <div class="mt10">