diff --git a/lib/http.js b/lib/http.js
index 2e12ab1..425b146 100644
--- a/lib/http.js
+++ b/lib/http.js
@@ -39,7 +39,7 @@ var HTTPObject = function(engine) {
         },
         "unixnowms": function(diff) {   // e.g. {unixnowms -300000} (milliseconds)
             var t = parseInt(diff);
-            return new Date().getTime() - t;
+            return Math.floor(new Date().getTime()) - t;
         }
     };
     this.connectTimeout = 0;