Javascript - Blackberry - force screen refresh

Question

Javascript/HTML - for Blackberry - force screen refresh

I am writing a web based application for Blackberry users with some Ajax data retreival. Because response time is poor I want to add a visual cue that data is loading like a spinner or hourglass

To do this I tried various like style.display

document.getElementById('spinner').style.display = 'none';
document.getElementById('spinner').style.display = 'none';

This works in IE and mozilla, but on Blackberry (OS 4.6) Browser, it does not work. I suspect that the screen does not refresh.

My question: How can I force a screen refresh -or- what other technique might accomplish what I want to do.