clearSignature Snippet

Note: the 3 pieces of code you need to customize are in bold below:

var params = arguments[0],

$ = skuid.$;

// get signature canvas and reset

var sig = $("#idSign");

sig.jSignature("reset");

// get signature field, set to null and save model

var model = skuid.model.getModel('Contact');

var row = model.getFirstRow();

var sigField = 'Signature__c';

model.updateRow(row,sigField,null);