diff --git a/src/api/mod.rs b/src/api/mod.rs
index f0d9233..f3c447c 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -171,12 +171,7 @@ pub async fn get_class(Query(params): Query<FilterByClassQuery>) -> impl IntoRes
     for record in rdr.records() {
         let record = match record {
             Ok(x) => x,
-            Err(_) => {
-                return (
-                    StatusCode::UNPROCESSABLE_ENTITY,
-                    Json(json!({ "errore": "Formato non supportato"})),
-                )
-            }
+            Err(_) => continue,
         };
         for (i, cell) in record.iter().enumerate() {
             if cell == params.classe {
diff --git a/static/index.js b/static/index.js
index 01faee5..15bdd6c 100644
--- a/static/index.js
+++ b/static/index.js
@@ -54,7 +54,7 @@ function load_classes(id) {
       }
       for (let i = 0; i < data.length; i++) {
         const option = document.createElement("option");
-        option.value = i;
+        option.value = i + 1;
         option.text = i + 1;
         select.appendChild(option);
       }
@@ -87,12 +87,14 @@ function make_teacher_table(id, teacher) {
         th.scope = "row";
         th.textContent = weekday;
         tr.appendChild(th);
-        data[weekday].forEach((teacher_class) => {
-          let td = document.createElement("td");
-          td.textContent = teacher_class;
-          tr.appendChild(td);
-        });
-        tbody.appendChild(tr);
+        if (data[weekday] == null) {
+          data[weekday].forEach((teacher_class) => {
+            let td = document.createElement("td");
+            td.textContent = teacher_class;
+            tr.appendChild(td);
+          });
+          tbody.appendChild(tr);
+        }
       });
       table.appendChild(tbody);
       document.getElementById("table").removeAttribute("aria-busy");
@@ -123,12 +125,14 @@ function make_student_table(id, student_class) {
         th.scope = "row";
         th.textContent = weekday;
         tr.appendChild(th);
-        data[weekday].forEach((student_class) => {
-          let td = document.createElement("td");
-          td.textContent = student_class;
-          tr.appendChild(td);
-        });
-        tbody.appendChild(tr);
+        if (data[weekday] != null) {
+          data[weekday].forEach((student_class) => {
+            let td = document.createElement("td");
+            td.textContent = student_class;
+            tr.appendChild(td);
+          });
+          tbody.appendChild(tr);
+        }
       });
       table.appendChild(tbody);
       document.getElementById("table").removeAttribute("aria-busy");