diff --git a/src/python/ripe_demo/static/js/ripe.js b/src/python/ripe_demo/static/js/ripe.js
index 8909641dd..b1e8b5bb7 100644
--- a/src/python/ripe_demo/static/js/ripe.js
+++ b/src/python/ripe_demo/static/js/ripe.js
@@ -777,9 +777,7 @@ ripe.Ripe.prototype.signin = function(username, password, options, callback) {
         }
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.getConfig = function(options, callback) {
@@ -803,19 +801,19 @@ ripe.Ripe.prototype.getDefaults = function(options, callback) {
     options = typeof options === "function" ? {} : options;
     options = this._getDefaultsOptions(options);
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback(result ? result.parts : null);
+    return this._cacheURL(options.url, options, function(result, isValid) {
+        callback && callback(isValid ? result.parts : result, isValid);
     });
 };
 
 ripe.Ripe.prototype.getOptionals = function(options, callback) {
-    return this.getDefaults(options, function(defaults) {
+    return this.getDefaults(options, function(defaults, isValid) {
         var optionals = [];
         for (var name in defaults) {
             var part = defaults[name];
             part.optional && optionals.push(name);
         }
-        callback(optionals);
+        callback && callback(optionals, isValid);
     });
 };
 
@@ -824,8 +822,8 @@ ripe.Ripe.prototype.getCombinations = function(options, callback) {
     options = typeof options === "function" ? {} : options;
     options = this._getCombinationsOptions(options);
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result.combinations);
+    return this._cacheURL(options.url, options, function(result, isValid) {
+        callback && callback(isValid ? result.combinations : result, isValid);
     });
 };
 
@@ -899,9 +897,12 @@ ripe.Ripe.prototype._requestURL = function(url, options, callback) {
     var request = new XMLHttpRequest();
 
     request.addEventListener("load", function() {
+        var result = null;
         var isValid = this.status === 200;
-        var result = JSON.parse(this.responseText);
-        callback && callback.call(context, isValid ? result : null, isValid, this);
+        try {
+            result = JSON.parse(this.responseText);
+        } catch (error) {}
+        callback && callback.call(context, result, isValid, this);
     });
 
     request.open(method, url);
@@ -1410,9 +1411,7 @@ ripe.Ripe.prototype.oauthAccessToken = function(code, options, callback) {
         }
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.oauthLogin = function(accessToken, options, callback) {
@@ -1426,9 +1425,7 @@ ripe.Ripe.prototype.oauthLogin = function(accessToken, options, callback) {
             access_token: accessToken
         }
     });
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 if (typeof require !== "undefined") {
@@ -1448,9 +1445,7 @@ ripe.Ripe.prototype.getOrders = function(options, callback) {
         auth: true
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.getOrder = function(number, options, callback) {
@@ -1463,9 +1458,7 @@ ripe.Ripe.prototype.getOrder = function(number, options, callback) {
         auth: true
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.createOrder = function(number, options, callback) {
@@ -1514,9 +1507,7 @@ ripe.Ripe.prototype.setOrderStatus = function(number, status, options, callback)
         method: "PUT"
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 if (typeof require !== "undefined") {
@@ -1535,9 +1526,7 @@ ripe.Ripe.prototype.getSizes = function(options, callback) {
         method: "GET"
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.sizeToNative = function(scale, value, gender, options, callback) {
@@ -1554,9 +1543,7 @@ ripe.Ripe.prototype.sizeToNative = function(scale, value, gender, options, callb
         }
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.sizeToNativeB = function(scales, values, genders, options, callback) {
@@ -1586,9 +1573,7 @@ ripe.Ripe.prototype.sizeToNativeB = function(scales, values, genders, options, c
     });
     options = this._build(options);
 
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.nativeToSize = function(scale, value, gender, options, callback) {
@@ -1605,9 +1590,7 @@ ripe.Ripe.prototype.nativeToSize = function(scale, value, gender, options, callb
         }
     });
     options = this._build(options);
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 ripe.Ripe.prototype.nativeToSizeB = function(scales, values, genders, options, callback) {
@@ -1637,9 +1620,7 @@ ripe.Ripe.prototype.nativeToSizeB = function(scales, values, genders, options, c
     });
     options = this._build(options);
 
-    return this._cacheURL(options.url, options, function(result) {
-        callback && callback(result);
-    });
+    return this._cacheURL(options.url, options, callback);
 };
 
 if (typeof require !== "undefined") {