It is not possible with client-side javascript.
Some browsers accept the Content-Disposition header, but this
must be added by the server. Taking the form:-
` Content-Disposition: attachment; filename=filename.ext `
http://classicasp.aspfaq.com/general/how-do-i-prompt-a-save-as-dialog-for-an-accepted-mime-type.html
http://support.microsoft.com/kb/q260519/
The complete comp.lang.javascript FAQ is at
http://jibbering.com/faq/
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