ajax/javascript function that passes data to the server

ajax/javascript function that passes data to the server where it is saved as a file using [login to view URL] the server the data and the filename to save the data as. The function must pass For example if the function is called 'save' then save(data, '[login to view URL]') would pass 'data' to the server where it would be saved as a file called '[login to view URL]' in the current directory. Prefer this is done using YUI library.