xml: save file

what is the correct syntax to save a xml file in javascript? I have tried:

Code:

---

  var oDOM = new ActiveXObject("Microsoft.XMLDOM");
  oDOM.load("test.xml");
  oDOM.Save("test.xml");

---

but I get object does not support this on the save.

Code:

---

  var oDOM = new ActiveXObject("Microsoft.XMLDOM");
  oDOM.load("test.xml");
  oDOM.save("test.xml");

---

This gives permission denied

Thanks