ocx control and javascript

I am trying to communicate with an ocx control hosted in an aspx web page. The ocx control downloads and instantiates correctly (checked dowbnloaded program files and the registry) but talking to the ocx control using javsacript yields no response.

Page snippet:

function GetData() {

alert('here');
var ctrl = document.FC;
ctrl.Trace_Reference = 'qqq';
alert(ctrl.Trace_Reference);
var stringData = ctrl.Trace_Data;
alert(stringData);

return false;

}

Any ideas? The ocx control works fine when tested in a windows form.