Add file upload

assets/script.js

@@ -537,4 +537,24 @@ if ("loading" === document.readyState) {
     document.addEventListener("DOMContentLoaded", initAjax);
 } else {
     setTimeout(initAjax, 0);
+}
+
+function uploadFile() {
+    const fileInput = document.getElementById('fileInput');
+    const file = fileInput.files[0];
+    let formData = new FormData();
+    formData.append('userfile', file);
+
+    let xhr = new XMLHttpRequest();
+    xhr.open('POST', '__URL__', true);
+
+    xhr.onload = function () {
+        if (xhr.status === 200) {
+            document.getElementById('uploadStatus').innerHTML = 'File uploaded successfully.';
+        } else {
+            document.getElementById('uploadStatus').innerHTML = 'Error uploading file.';
+        }
+    };
+
+    xhr.send(formData);
 }