title: Javascript: Save json data as a file on the server / user's hard disk
body: <p>I have developed an app that allows the user to fill out text fields with information. I want them to be able to press a button that will make a file with data (a really long array with info on what they typed and where it should go) so they can reload the data at a later date. I don't have a server now, and I am sending this app as a standalone html app to my friends for their use until I get hosing / mySql / etc. 
  Is there a way that when they click on a button it will take this data (saved as an array, <code>save_data</code>), put it into a file, and basically begin the download process from their web-browser? 
  And later on, what tech would I need to be looking into to save this into online user accounts?</p>