Retrieve Header Fields on Forms in Dynamics 365

To obtain a field from the header section of any form using JavaScript, the key is to append "header_" before the actual field name. For instance, if you want to retrieve the 'status' field (with the schema name 'statuscode') and the 'name' field from the case form, which are located in the header section, you should use "header_statuscode" and "header_name" respectively.
The following examples illustrate how to achieve this:

Javascript cdoe samples-

// Retrieving fields from the header section on the form

function getHeaderField(executionContext) {

  var formContext = executionContext.getFormContext();

  var status = formContext.getAttribute("header_statuscode").getValue();

  // Other example - hiding the 'header_fieldname' control

  Xrm.Page.getControl("header_fieldname").setVisible(false);

}

// Retrieving fields from form sections or tabs

function getField(executionContext) {

  var formContext = executionContext.getFormContext();

  var status = formContext.getAttribute("statuscode").getValue();

  // Other example - hiding the 'fieldname' control

  Xrm.Page.getControl("fieldname").setVisible(false);

}