Is it possible to show/hide a subtab conditionally? I am looking to show a subtab only if there is a value in a custom field on a sales order and hide another subtab based on the same parameter.

Is it a custom tab or netsuite native one? Is this in a single account or spread across multiple like in a suiteapp/bundle?

custom tab and single account.

You could certainly hide it by setting the display,

jQuery('#tabid').css('display', 'none')

and reveal with

jQuery('#tabid').css('display', '')

Ok. I can do that.