diff --git a/static/index.js b/static/index.js
index ae854e6..a46c7e6 100644
--- a/static/index.js
+++ b/static/index.js
@@ -20,11 +20,12 @@ function load_teachers(id) {
     .then((data) => {
       sessionStorage.setItem("teachers", JSON.stringify(data));
       let i = 0;
+      const list = document.getElementById("teachers");
+      list.innerHTML = "";
       data.forEach((el) => {
-        const select = document.getElementById("teachers");
         const option = document.createElement("option");
         option.value = el;
-        select.appendChild(option);
+        list.appendChild(option);
         i++;
       });
     });
@@ -34,8 +35,14 @@ function load_classes(id) {
   fetch(`/api/classi?id=${id}`)
     .then((response) => response.json())
     .then((data) => {
+      const select = document.getElementById("year");
+      for (let i = 0; i < select.children.length; i++) {
+        if (!select.children[i].hasAttribute("disabled")) {
+          select.removeChild(select.children[i]);
+          i--;
+        }
+      }
       for (let i = 0; i < data.length; i++) {
-        const select = document.getElementById("year");
         const option = document.createElement("option");
         option.value = i;
         option.text = i + 1;
@@ -129,8 +136,14 @@ function select_type() {
 function load_section() {
   let data = JSON.parse(sessionStorage.getItem("classes"));
   let year = document.getElementById("year").value;
+  const select = document.getElementById("section");
+  for (let i = 0; i < select.children.length; i++) {
+    if (!select.children[i].hasAttribute("disabled")) {
+      select.removeChild(select.children[i]);
+      i--;
+    }
+  }
   Object.keys(data[year]).forEach((el) => {
-    const select = document.getElementById("section");
     const option = document.createElement("option");
     option.value = el;
     option.text = el;
@@ -142,8 +155,14 @@ function load_major() {
   let data = JSON.parse(sessionStorage.getItem("classes"));
   let year = document.getElementById("year").value;
   let section = document.getElementById("section").value;
+  let select = document.getElementById("major");
+  for (let i = 0; i < select.children.length; i++) {
+    if (!select.children[i].hasAttribute("disabled")) {
+      select.removeChild(select.children[i]);
+      i--;
+    }
+  }
   data[year][section].forEach((el) => {
-    const select = document.getElementById("major");
     const option = document.createElement("option");
     option.value = el;
     option.text = el;