Adding the ability for javascript from problems to execute more intelligently;…

Adding the ability for javascript from problems to execute more intelligently; for example, errors from javascript included in the returned html will show up in the console when using this mechanism.

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

@@ -31,8 +31,20 @@ class @Problem
     else
       $.postWithPrefix "#{@url}/problem_get", (response) =>
         @el.html(response.html)
+        @executeProblemScripts()
         @bind()
 
+  executeProblemScripts: ->
+    @el.find(".script_placeholder").each (index, placeholder) ->
+      s = $("<script>")
+      s.attr("type", "text/javascript")
+      s.attr("src", $(placeholder).attr("data-src"))
+
+      # Need to use the DOM elements directly or the scripts won't execute
+      # properly.
+      $('head')[0].appendChild(s[0])
+      $(placeholder).remove()
+
   check: =>
     Logger.log 'problem_check', @answers
     $.postWithPrefix "#{@url}/problem_check", @answers, (response) =>