You can drag files from your computer to a form to upload them.
This functionality is supported in Firefox 3.6 or later and Chrome. Support will be
added for other web browsers as they implement the HTML5 specification.
Navigate to the record.
On your computer, browse to the files to attach.
Select the files in the file browser, and then drag them over the form.
Release the mouse button to begin the upload.
When the upload is complete, the file name is added to the attachments
header. Upload speed depends on the file size and the speed of your network
Warning: Do not navigate away from the record
while an upload is in progress. The upload must be completed for the
file to be attached.