diff --git a/web/assets/js/index.js b/web/assets/js/index.js
new file mode 100644
index 0000000..42e3a2c
--- /dev/null
+++ b/web/assets/js/index.js
@@ -0,0 +1,9 @@
+function rotateMirror(mirror) {
+    let angle = 0;
+    if (mirror.style.transform == "") {
+        angle = 0;
+    } else {
+        angle = parseInt(mirror.style.transform.split("(")[1].split("deg")[0])%360;
+    }
+    mirror.style.transform = `rotate(${angle+45}deg)`;
+}
\ No newline at end of file