add fix

@@ -187,7 +187,7 @@ Captcha.prototype = {
                 result.push(val % 4);
             });
 
-        if (this.$_____trojanYohobuy.val()) {
+        if (this.$_____trojanYohobuy && this.$_____trojanYohobuy.val()) {
             result = [];
             result.push(this.$_____trojanYohobuy.val());
         }