Saving text in Dashcode

I'm trying to create a widget for a iBooks textbook in Dashcode that will allow users to enter a response to a prompt in a text area. I would like that text to save locally for later review. Since this is my first time programming in Javascript, is there a way to do this?

I understand that Dashcode widgets include something called a "key" that will allow data to be stored and retrieved upon the start of another session. If someone could give me the code to make this widget work, that would be great!

Here are the IDs of the fields in the widget

Text area has an ID of "textarea" (go figure!)
Key for saving entered text is "textareadata"

Thanks, in advance, for your help!