web engine always returns 0 for getTimezoneOffset()

from PyQt5.Qt import (QApplication, QWebEngineView)                                                                                                                                                                                            
                                                                                                                       
app = QApplication([])                                                                                                 
w = QWebEngineView()                                                                                                   
w.setHtml('<script>alert(new Date().getTimezoneOffset())</script>')                                                    
w.show()                                                                                                               
                                                                                                                       
app.exec_()