javascript input values to python

from PyQt4 import QtCore, QtGui, QtWebKit
import WebGui
import Part
import FreeCADGui, FreeCAD

html = """
<HTML>
<HEAD>
<TITLE>Test Input</TITLE>
<SCRIPT LANGUAGE="JavaScript">
function testResults (form) {
    var lenVar = form.boxlength.value;
    var widthVar = form.boxwidth.value;
    var heightVar = form.boxheight.value;
    pyObj.newBox(lenVar,widthVar,heightVar);
}</SCRIPT>
</HEAD>
<BODY>
<FORM NAME="myform" ACTION="" METHOD="GET">
  <table> <TR>
      <TH align=right>Box Length:
      <TD><INPUT TYPE="text" NAME="boxlength" VALUE=""><TR>
      <TH align=right>Box Width:
      <TD><INPUT TYPE="text" NAME="boxwidth" VALUE=""><TR>
      <TH align=right>Box Height:
      <TD><INPUT TYPE="text" NAME="boxheight" VALUE=""><TR> </table>
<INPUT TYPE="button" NAME="button" Value="Draw Box" onClick="testResults(this.form)">
</FORM> </BODY> </HTML>
"""
class TestClass(QtCore.QObject):
    @QtCore.pyqtSlot(str,str,str)
    def newBox(self, msg1,msg2,msg3):
        l = float(msg1); w= float(msg2);h = float(msg3)
        box1 = Part.makeBox(l,w,h)
        Part.show(box1)

myObj = TestClass()
WebGui.openBrowser("http://javascriptBox")
a = QtGui.qApp
mw = a.activeWindow()
v= mw.findChild(QtWebKit.QWebFrame)
v.setHtml(html)
curr1 = v.page()
frame1 = curr1.currentFrame()
frame1.addToJavaScriptWindowObject("pyObj", myObj)