diff --git a/js/IVPAIDAdUnit.js b/js/IVPAIDAdUnit.js
index cb05529..9f84427 100644
--- a/js/IVPAIDAdUnit.js
+++ b/js/IVPAIDAdUnit.js
@@ -15,6 +15,22 @@ var METHODS = [
     'unsubscribe'
 ];
 
+// for avoiding argument leaking
+var METHODS_LENGTH = {
+    'handshakeVersion': 2,
+    'initAd': 7,
+    'startAd': 1,
+    'stopAd': 1,
+    'skipAd': 1, // VPAID 2.0 new method
+    'resizeAd': 4,
+    'pauseAd': 1,
+    'resumeAd': 1,
+    'expandAd': 1,
+    'collapseAd': 1,
+    'subscribe': 3,
+    'unsubscribe': 2
+};
+
 var EVENTS = [
     'AdLoaded',
     'AdStarted',
@@ -257,6 +273,7 @@ IVPAIDAdUnit.prototype.getAdIcons = function(callback) {};
 IVPAIDAdUnit.prototype.setAdVolume = function(volume, callback) {};
 
 addStaticToInterface(IVPAIDAdUnit, 'METHODS', METHODS);
+addStaticToInterface(IVPAIDAdUnit, 'METHODS_LENGTH', METHODS_LENGTH);
 addStaticToInterface(IVPAIDAdUnit, 'GETTERS', GETTERS);
 addStaticToInterface(IVPAIDAdUnit, 'SETTERS', SETTERS);
 addStaticToInterface(IVPAIDAdUnit, 'EVENTS',  EVENTS);
diff --git a/js/VPAIDAdUnit.js b/js/VPAIDAdUnit.js
index a40fcc2..1339b48 100644
--- a/js/VPAIDAdUnit.js
+++ b/js/VPAIDAdUnit.js
@@ -62,7 +62,7 @@ IVPAIDAdUnit.METHODS.forEach(function(method) {
     if (ignores.indexOf(method) !== -1) return;
 
     VPAIDAdUnit.prototype[method] = function () {
-        var ariaty = IVPAIDAdUnit.prototype[method].length;
+        var ariaty = IVPAIDAdUnit.METHODS_LENGTH[method];
         // TODO avoid leaking arguments
         // https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#32-leaking-arguments
         var args = Array.prototype.slice.call(arguments);