What do you do if you want to give users a way to close a pop-up window that they’re viewing? Provide a close link, of course. Just select the text or image that you want to use as a link, and then in the Link field of the Property inspector enter the following code: javascript:self.close();. Want the window to close automatically if the user leaves the page without closing it? Add the script to an onBlur event in the <body> tag!
As if that isn’t easy enough, there’s a free extension, DWfaq Close Pop-up Window, which you can apply from the Behaviors panel. You can find the extension at http://www.dwkillertips.com/go/20.