Quote the starts with expression id^

TNL-1240

common/lib/xmodule/xmodule/js/fixtures/problem_content_1240.html

+<h2 class="problem-header">Problem Header</h2>
+
+<div class='problem-progress'></div>
+
+<div class="problem">
+  <p>${_("Problem Content")}</p>
+
+  <div class="action">
+    <input type="hidden" name="problem_id" value="1">
+
+    <input type="text" name="input_example_1.Test" id="input_example_1.Test" value="" class="math" />
+    <span id="display_example_1"></span>
+    <span id="input_example_1_dynamath"></span>
+
+    <input class="check" type="button" value="Check">
+    <input class="reset" type="button" value="Reset">
+    <input class="save" type="button" value="Save">
+    <button class="show"><span class="show-label">Show Answer(s)</span> <span class="sr">(for question(s) above - adjacent to each field)</span></button>
+    <a href="/courseware/6.002_Spring_2012/${ explain }" class="new-page">Explanation</a>
+    <div class="submission_feedback"></div>
+  </div>
+</div>

common/lib/xmodule/xmodule/js/spec/capa/display_spec.coffee

@@ -78,6 +78,19 @@ describe 'Problem', ->
         [@problem.updateMathML, @stubbedJax, $('#input_example_1').get(0)]
       ]
 
+  describe 'bind_with_custom_input_id', ->
+    beforeEach ->
+      spyOn window, 'update_schematics'
+      MathJax.Hub.getAllJax.andReturn [@stubbedJax]
+      @problem = new Problem($('.xblock-student_view'))
+      $(@).html readFixtures('problem_content_1240.html')
+
+    it 'bind the check button', ->
+      expect($('div.action input.check')).toHandleWith 'click', @problem.check_fd
+
+    it 'bind the show button', ->
+      expect($('div.action button.show')).toHandleWith 'click', @problem.show
+
   describe 'renderProgressState', ->
     beforeEach ->
       @problem = new Problem($('.xblock-student_view'))

common/lib/xmodule/xmodule/js/src/capa/display.coffee

@@ -25,7 +25,7 @@ class @Problem
     window.update_schematics()
 
     problem_prefix = @element_id.replace(/problem_/,'')
-    @inputs = @$("[id^=input_#{problem_prefix}_]")
+    @inputs = @$("[id^='input_#{problem_prefix}_']")
     @$('div.action input:button').click @refreshAnswers
     @checkButton = @$('div.action input.check')
     @checkButtonCheckText = @checkButton.val()