I'm sure this must be a common requirement but I haven't been able to find what I need.

I have a Visualforce page with a standard controller.  The user updates one field on that page then clicks a button to update the record and then display a different visualforce page with a custom controller which uses the value that has just been updated.

How can I ensure that the first update has completed before the new page is displayed?

I originally had two buttons, one to 'Update' and one to display new page.  However, I fear impatient users will continue before the update has completed, so want to combine into one and bake in the control.  I have used a Javascript function to pass parameters and display the second page.

Thanks,
Mike.