bug修改

@@ -63,7 +63,8 @@ class Index extends Api
                 ->order('exam_time asc')
                 ->select();
             foreach ($exam_list as &$v) {
-                $v['countdown'] = ceil(($v['exam_time']-time())/86400);
+                $countdown = ceil(($v['exam_time']-time())/86400);
+                $v['countdown'] = $countdown > 0 ? $countdown : 0;
             }
             $exam = $exam_list[0];
         }else{
@@ -71,7 +72,8 @@ class Index extends Api
             $exam = Exam::field('id,name,nickname,exam_time')
                 ->order('exam_time asc')
                 ->find();
-            $exam['countdown'] = ceil(($exam['exam_time']-time())/86400);
+            $countdown = ceil(($exam['exam_time']-time())/86400);
+            $exam['countdown'] = $countdown > 0 ? $countdown : 0;
         }
         // 轮播图
         $banner_list = IndexBanner::order('createtime desc')->field('id,image,url')->select();