Which Modal Popup to use to add/edit data

I am developing a large asp.net ajax website. To provide better user experience, I want the user to perform Add/Edit on the same page using a Modal Popup without navigating to another page. I have tried using ajaxcontroltoolkit ModalPopup but it comes with many issues including:

1. The ModalPopup closes on every page postback.

2. The ModalPopup shows up again if I refresh the page after performing Add/Edit.

Can someone guide to me a better modal popup (could be jquery based) which can be used to add/edit data. An example would be appreciated. Thanks.