Changing CRM form properties in Javascript doesn't trigger onChange

I've just learnt the hard way that when you change a field value on a MS CRM 2011 form via JavaScript it doesn't automatically trigger any onChange event which is wired up to that field.
To manually trigger any onChange event you do the following

Xrm.Page.getAttribute('myfieldname').fireOnChange();

or better yet, if you use a custom library to simplify your read

SetAttributeValue = function (attributeString, value) {
 var attribute = Xrm.Page.getAttribute(attributeString);
 
 if (attribute) {
  attribute.setValue(value);
  // manually fire the onChange event.
  attribute.fireOnChange();
 }
};