The EJS will be loaded into your browser(with your permission) and you will be able to save/modify the ejs source code, if you clicked the above button (right under the simulation) labeled as "load ejs as signed applet".
Actually, it is the same for all the simulations created with EJS on our server.
So, please click the button. And you will find out how the ariables are defined, what are the relations used. You can save it if you click the save button in the EJS and you can even modify the code and generate new simulation (click green triangle).