create and save a .csv to server

I have a problem where I need to create a csv, then save it to the server.  This needs to be done by one click of a button. 

What I have so far:

I have a popup with a table of textboxes, the user eneters data into these txtboxes,  when complete the click a button that says save.  A .csv is created, however a popup appears asking the user to save the .csv to there computer.  I do not want this to happen, instead when the user clicks save, the file is automatically created, then saved to then uploaded to the server.

Is this possible?  If so how?  I have a string in a .csv format, I just need that to be saved to a file and automatically uploaded to the server.
...