Saving file from server to client's PC

[BlueMelon]

I have recently stumbled across the selectFileForDownload(str) function with no surprise of not finding much documentation.

What I want to do is download a file from the server to my PC using a save file dialog-esk UI.

This is what the function gives clientside for:
selectFileForDownload("/levels/graphics/images/test.png");


When I click the save button, nothing happens and the function doesn't return anything.

I haven't seen this function being used anywhere either...
And the lack of documentation doesn't help.

Is there another way to download a file from the server to a client's PC?

I want to avoid uploading it to a web server and getting the client to download it from there...

I have also tried different arguments for the function with no luck.