Is there a way to allow a user, after he has created a vector graph on a javascript svg canvas using a browser, to download this file to their local filesystem?
SVG is a total new field for me so please be patient if my wording is not accurate.
It might be possible using the regular "Save" browser command, but it won't just save the SVG canvas, it will save the whole page.
I believe your best bet is to use AJAX and send the whole SVG XML data as POST data to a server script, and have that script just send back the POST data with the header Content-Disposition: attachment; filename=yourfile.svg.
(Under PHP, you can get the raw POST contents with file_get_contents('php://input').)