InfoPath Dev

 I have a very basic qrules injected InfoPath 2010 form that only uses the datediff function to calculate the different between 2 dates. Its set to be a browser based form

In InfoPath designer the datediff command is set to run when the button is pushed, it works like that in Preview Mode

But when I admin-approved publish the form to SharePoint 2013 and add it to a form library the form loads correctly but it doesn't display the result of the calculation when i click the button but will if i then click the Save, Save As or Print preview ribbon buttons. If I click save the dialog to set the file name opens but you can see the result in the background

Hi - set the postback on your button to always - this is under the button properties on the browser tab.

 Thanks Hilary, That was it exactly. Obvious now when I think about it