How to use pyqt5 browser to Realize printing function

when I use pyqt5 browser to Visit specific web pages ,in this pages has a print button,but when I click this print button the browser has no response.in Firefox browser,after I click print button,the printpreview is showing,and the i can choose printer.

According to this, print preview is not yet available for QtWebEngine, so you can only directly print.

To catch the print request of a page, you need to connect the printRequested() signal.

class PrintTest(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(PrintTest, self).__init__(parent)
        layout = QtWidgets.QHBoxLayout(self)
        self.view = QtWebEngineWidgets.QWebEngineView()
        layout.addWidget(self.view)
        self.page = QtWebEngineWidgets.QWebEnginePage(self)
        self.view.setPage(self.page)
        self.page.printRequested.connect(self.printRequested)
        # load a page that has a print request
        self.view.load(QtCore.QUrl(
            "https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_print"))

    def printRequested(self):
        defaultPrinter = QtPrintSupport.QPrinter(
            QtPrintSupport.QPrinterInfo.defaultPrinter())
        dialog = QtPrintSupport.QPrintDialog(defaultPrinter, self)
        if dialog.exec():
            # printer object has to be persistent
            self._printer = dialog.printer()
            self.page.print(self._printer, self.printResult)

    def printResult(self, success):
        if success:
            QtWidgets.QMessageBox.information(self, 'Print completed', 
                'Printing has been completed!', QtWidgets.QMessageBox.Ok)
        else:
            QtWidgets.QMessageBox.warning(self, 'Print failed', 
                'Printing has failed!', QtWebEngineWidgets.QMessageBox.Ok)
            self.printRequested()
        del self._printer