SigPad API
I had difficulties getting Thomas J Bradley's HTML5 Signature Pad to let me to use its API without resetting the field. This Github issue explains a workaround:https://github.com/thomasjbradley/signature-pad/issues/13
He is saving the signature, declaring the api variable, then regenerating the signature.
I needed to use the .getSignatureImage() api function which allows me to turn the signature into a base64 string so I could store the signature in a database.