Question about a query

[alexandros kalivas]

Hi,
I have been trying to learn how to use your platform. I followed this tutorial https://devcenter.appery.io/tutorials... and now I want to create a query with two parameters. The maker and the model. I created a second inputbox for the model, went to the mapping page, linked the second inputbox and switched the existing code for the simple query(return '{"Maker":"'+value+'"}';) and used this:
var Maker = localStorage.getItem("Maker");
var Model = localStorage.getItem("Model");
var whereObject = {$and: [{"Maker": "'+Maker+'"},{"Model":"'+Model+'"}]};
return JSON.stringify(whereObject);
It is not working.What am I doing wrong?
Thank you for your time.