update

src/components/studyStudent.vue

@@ -5648,17 +5648,17 @@ export default {
     },
     setContent(bool) {
       this.contentDialog = bool
-      if (bool && this.mlDialog) {
+      if (bool && this.mlDialog && document.querySelector('.workd_media')) {
         document.querySelector('.workd_media').style.height = "650px"
-      } else {
+      } else if(document.querySelector('.workd_media')){
         document.querySelector('.workd_media').style.height = "auto"
       }
     },
     setContent2(bool) {
       this.mlDialog = bool
-      if (bool && this.contentDialog) {
+      if (bool && this.contentDialog && document.querySelector('.workd_media')) {
         document.querySelector('.workd_media').style.height = "650px"
-      } else {
+      } else if(document.querySelector('.workd_media')){
         document.querySelector('.workd_media').style.height = "auto"
       }
     },