Editable Invoice

Editable Invoice is based on the Editable, Printable Invoice by Chris Coyer and others (http://css-tricks.com/editable-invoice-v2/)

Changes

I've added a removable discount field and changed the title to include the date, as I file invoices by date.

The date is also automatically set to today, and the document title automatically updates when any change is made to the invoice number, date, or customer name.