diff --git a/index.php b/index.php
index b47b5d2..d79e1df 100644
--- a/index.php
+++ b/index.php
@@ -20,6 +20,8 @@ if ($_SERVER['REQUEST_METHOD'] == "POST") {
       $data[$key] = $v;
     } else if (preg_match('/^date_(\d\d\d\d-\d\d-\d\d)$/', $key, $matches) && $v == "on") {
       $data['dates'][] = $matches[1];
+    } else if ($key == "tagx" && $v == "on") {
+      $data['dates'][] = $key;
     } else {
       echo "Invalid value " . htmlspecialchars($v) . " for key " . htmlspecialchars($key);
       exit;