exchange2013 OWA UserPick Page Return Value

I want to use my user picker page to replaced the system default page,I use jquery change the pick button's click event  to popup my user picker page;

but I don't know how to throw js return the selected user email to the textbox,I try to find the js in Owa\15.0.466.13\Owa2\scripts\ but read these script is too difficult!