Figured it out with a little help. In the script editor window I chose the postSign event and added the following JS:
form1.page1.ClaimSignature::postSign - (JavaScript, client)
var date = new Date();
var day = date.getDate();
var month = date.getMonth() + 1;
var monthstring = (month , 10 ? "0" + month : month)
var year = date.getFullYear();
var datestring = year + "-" + monthString + "-" + (day < 10 ? "0" + day : day);
ClsimSigDate.rawValue = dateString;
Hope this helps someone else save time.