fix bug

apps/exams/_static/js/public_exam_3g.js

@@ -59,8 +59,10 @@ $(function() {
         }
         }
 
 
         if (limit > 0 && question_num >= limit) {
         if (limit > 0 && question_num >= limit) {
-            let page = $("#ex" + question_num + ' .next')
-            page.removeClass('next_question');
+            let page = $("#ex" + question_num + ' .next');
+            page.unbind('click', function () {
+
+            })
             page.attr({'style': 'background:rgba(245,166,35,1);'});
             page.attr({'style': 'background:rgba(245,166,35,1);'});
             page.text('去支付');
             page.text('去支付');
         }
         }