saveSignature Snippet

Note: the 3 pieces of code you need to customize are in bold below:
  1. Exact name of your Model
  2. Exact name of your custom Signature field
  3. Exact name of the Unique Id that you assign to your custom Signature component

var params = arguments[0],
   $ = skuid.$;
var model = skuid.model.getModel('Contact'),
    row = model.getFirstRow(),
    sigField = 'Signature__c';
// get signature from id
var sig = $("#idSign");
var sigData = sig.jSignature("getData", "base30");
// update signature text field SF and save
model.updateRow(row,sigField,sigData[0] + ',' + sigData[1]);
model.save();