diff --git a/js/urlon.js b/js/urlon.js
index b94002a..cb97b1b 100644
--- a/js/urlon.js
+++ b/js/urlon.js
@@ -26,7 +26,7 @@ URLON = {
 				return '_' + res.join('&') + ';';
 			}
 			// String or undefined
-			return '=' + encodeString((input || "null").toString());
+			return '=' + encodeString((input !== null ? input : "null").toString());
 		}
 
 		return stringify(input).replace(/;+$/g, '');