first commit

app/save.php

@@ -0,0 +1,23 @@
+<?php
+
+if ($_SERVER["REQUEST_METHOD"] == "POST") {
+
+    $number = $_POST['number'];
+
+    if (empty($number)) {
+        echo "Invalid input";
+        exit;
+    }
+
+    $file = 'data.csv';
+
+    $handle = fopen($file, 'a');
+
+    // Save ONLY number (no timestamp)
+    fputcsv($handle, [$number]);
+
+    fclose($handle);
+
+    echo "Saved!";
+}
+?>