add dropdown component

lib/utility.js

@@ -3,6 +3,12 @@ import { init, r, lang } from "./utility/lgres";
 import { get, post, upload } from "./utility/request";
 import { nullOrEmpty, contains, endsWith, padStart } from "./utility/strings";
 
+let g = typeof globalThis !== 'undefined' ? globalThis : self;
+
+function isPositive(n) {
+    return !isNaN(n) && n > 0;
+}
+
 export {
     // cookie
     getCookie,
@@ -20,5 +26,8 @@ export {
     nullOrEmpty,
     contains,
     endsWith,
-    padStart
+    padStart,
+    // variables
+    g as global,
+    isPositive
 }