Add more fields dynamically to dialog

Is it possible in an extension to have a button for the user to add another row of controls? Here's the scenario: A <video> tag can have any number of SOURCE tags. I'd like to add a [+] button so users can add another SOURCE tag row. However, I read that you can't use the document.write() function in an extension. So how do you achieve this effect? Thanks.

Take a look at the Recordset dialog. You can add as many fields as you like, and they get listed in a multiline text box (i.e. <textarea>).

HTH,

Randy