https://stackoverflow.com/questions/53421170/download-file-pyqt-browser

main.py

import sys 
from PyQt4 import QtCore, QtGui, QtWebKit

class Widget(QtGui.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        vlay = QtGui.QVBoxLayout(self)
        self.le = QtGui.QLineEdit()
        self.browser = QtWebKit.QWebView()
        self.le.returnPressed.connect(self._return_pressed)
        self.browser.setForwardUnsupportedContent(True)
        self.browser.page().unsupportedContent.connect(self.on_unsupportedContent)

    def on_return_pressed(self):
        self.browser.load(QtCore.QUrl(self.le.text()))

    def on_unsupportedContent(self, request):
        reply = self.browser.networkAccessManager().get(request)
        reply.finished.connect(self.on_finished)

    def on_finished(self):
        reply = self.sender()
        ba = reply.readAll()
        fileName = reply.url().fileName()
        file = QtCore.QFile(fileName)
        if file.open(QtCore.QFile.WriteOnly):
            file.write(ba)
            file.close()
        reply.deleteLater()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())