Is it possible to generate a file in javascript and then prompt the user to download ? 

What we would really like to do is the following : we want to make a small html form where an user can edit values in a table, and we would like to be able to generate a csv file from the form and prompt the user to save it on his hard drive. Is it possible in pure javascript ? If not, are there any workarounds ? 

Note : I know I could solve this by a round-trip to a server, sending the form and getting a csv file back, but the trick here is that there is no server, the html form will just be generated on a hard drive.