DHide/Show of div in web resource does not work

Hi

I have an HTML web resource which holds a div with a busy message and refers to the circular CRM progress graphic. This works when the web resource is first painted then it is hidden using JQuery:

    $('#loadingDiv').attr('style', 'display:none');

This successfully hides it.The user may then click another button requiring that busy we shown again. So the code:

    $('#loadingDiv').attr('style', 'display:block');

is used. However this does not work - the div remains hidden. I thought that this might be due to some other elements in the web resource which is fairly complex. However making no other change then adding an alert such as:

$('#loadingDiv').attr('style', 'display:block');
alert('message');

makes the div appear. Which makes me think it is something to do with web resource rendering.

Any ideas?

Thanks

Paul