Scribble provides a simple signature pad/scribble pad.
Add the class "scribble" to a textarea to allow the entry of a scribble, like this.
The scribble is stored as a base64 string in the textarea.
Add a class of "scribble" to a div to show the enclosed base64 string as an image.
This can be used as a Form Script field object, as in the following example.
{
"reference": "signature",
"type": "textbox",
"name": "Sign here",
"rows": 8,
"fieldClass": "scribble"
}