How to serialize an URL?

[wallytax]

Since I have a RubyOnRails-backend, I use parameters with '[]' suffix to retrieve the request parameter as array.

ListGrid.fetchData({'filter[]': [200, 300, 400]});

This works! It creates a request with "filter[]=200&filter[]=300&filter[]=400" in it. But what if I want to create such an URL myself? I've tried digging into the source code of fetchData() to see when and how the array is converted, but can't find it.

Is there a built-in function to do this? I'm using SmartClient 7.0rc2.