Return attachment with $.ajax call

To extend Darin's answer, here's how I did it:

I have a hidden form, with a hidden input element to be used to dynamically hold the values I wish to convert/export:

<form id="svg_export_form" method="POST" style="display:none;visibility:hidden">    <input type="hidden" name="svg" /></form>

Then I have this jQuery code to dynamically populate the elements with the post parameters, and then submit the form.

$('#svg_export_form > input[name=svg]').val(svg_code);$('#svg_export_form').attr('action','api/reports/convert/svg/to/png');$('#svg_export_form').submit();

And because the returned response (fro the api call) has a Content Disposition header set, this form submit action wont navigate the user away from the current page (but just returns the attachment) like a normal form submit, and thus still keeps the illusion of a typical Ajax submit :-)

You won't get the Save As dialog when using AJAX. If you want to get this dialog simply provide a normal link to the download file:

<a href="/SamplePage/ExportToExcel">download</a>

or if you need a POST request:

<form action="/SamplePage/ExportToExcel" method="post">    <input type="submit" value="download" /></form>

When you use AJAX to download a file the contents of this file is retrieved at the success callback but there's not much you can do with it: you cannot save it to the client computer and you cannot get Save As dialog.