Is there something like an 'onShow' event assignable to individual tab pages that I can use for this purpose?  The idea is to place three mutually exclusive sets of fields on each of three tab pages, with all the fields on each page required when the page is visible, but not required when not visible.  This is in an effort to minimize the chances of user error.  

Understand, the number of fields that would be on each page in the tab control is small (less than half a dozen), with many dozens of fields on the rest of the form, fields that are common to the tasks represented by the tabs in the tab control.  If that were not so, I'd just make three forms.

Is there a better way that creating a Javascript function to set fields being required, or not, invoked by an 'onshow' event?

Thanks

Ted