No. The server does. With IE this is even a bug:
If the server sets a pragma: No-cache header, IE refuses to store the thing at all. Even if it calls another program to display the (non-existing) file.
Such headers are sent to prevent caching, not to prevent the browser to call a plug-in.
+++ Despite being wrong in every important aspect, that is a very good analogy +++
Hex (in Darwin's Watch)