So, you would do most data-processing on the server side. But the data that your client-side application needs you will server to it, most likely via JSON. You

So, you would do most data-processing on the server side. But the data that your client-side application needs you will server to it, most likely via JSON. You can definately go too far and implement too much on the client side, and this is generally a bad approach. It's like with anything else. You need to figure out the balance between what you process on the server and what you process on the client.