Changing cursor in html screen.

I am developing a XML based intranet application.
I have a button to load data to screen. When I click the button I make a call to server and DLL and load data to an XML file and display it on the HTML page.
But it takes some time to display the data.
I want the cursor to look HourGlass when the process is going on.

I tried with document.body.style.cursor = "Wait"

It is nor working

Any help is appriciated.

Thanks
Ramdas