Edit in JSFiddle

// Only Load JS if the current page is PTNUI_NAVBAR
if (document.querySelector("[page='PTNUI_NAVBAR']")!==null) {	
  // Only Load JS if NOT Small Form Factor (SFF)
  if (document.querySelector('html').getAttribute('class').indexOf('psc_form-small') < 0) {
    cskLoadJS(getScriptUrl('CSK_NB_INIT_JS'), 'CSK_NB_INIT_JS', 'sCntr');
  }
}