diff --git a/web/template/home.gohtml b/web/template/home.gohtml
index 86f2a9c84..f01ccacf2 100755
--- a/web/template/home.gohtml
+++ b/web/template/home.gohtml
@@ -365,7 +365,7 @@
s.
+ :href="livestream.LectureHall.ExternalURL">
@@ -567,9 +567,7 @@
-
+
@@ -592,7 +590,7 @@
-
+
diff --git a/web/ts/entry/home.ts b/web/ts/entry/home.ts
index 9aacde30f..02ce8cb5c 100644
--- a/web/ts/entry/home.ts
+++ b/web/ts/entry/home.ts
@@ -4,3 +4,4 @@ export * from "../components/livestreams";
export * from "../components/course";
export * from "../components/servernotifications";
export * from "../components/main";
+export * from "../utilities/lecture-hall-validator"
diff --git a/web/ts/utilities/lecture-hall-validator.ts b/web/ts/utilities/lecture-hall-validator.ts
new file mode 100644
index 000000000..84aecb01d
--- /dev/null
+++ b/web/ts/utilities/lecture-hall-validator.ts
@@ -0,0 +1,6 @@
+export function isLectureHallValid(lectureHall: string): boolean {
+ const regex = /^\d{4}\.[A-Z0-9]{2}\.[A-Z0-9]{3,4}$/;
+ return regex.test(lectureHall);
+}
+
+(window as any).isLectureHallValid = isLectureHallValid;
\ No newline at end of file