JQM hide "Back button"

Hi,

I show "back button" with following code

<div data-role="page" id="itemDetailPage" data-add-back-btn="true" data-back-btn-text="Back" data-back-btn-theme="b">
...
</page>

but I need hide the button in some condition. May I use code to hide the button. Please give me a idea.

Thanks for your help

Mark