Sorry, I don't have a lot of time to answer this, but I would look into a modalPopup.
Modal Popup Demo. It pops up a window on your web page and you can grey out the background as they work in it. Once they click done it ungreys the background and the page looks as it did before they clicked the button. If that isn't what you want you could hide/unhide a div with your form contents in it. Have the button hide/unhide the div when someone clicks on it.
If these ideas don't help please let me know and I will see if I can offer a better solution. Best of luck!