Not enough arguments to XMLHttpRequest.open

Question

I am using AJAX2 as described here

https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest?redirectlocale=en-US&redirectslug=DOM/XMLHttpRequest/Using_XMLHttpRequest#Monitoring_progress

to monitor progress of ajax request, but i am receiving following error "TypeError: Not enough arguments to XMLHttpRequest.open."

Can anyone help why this error occuring?

My Code is:

                var oReq = new XMLHttpRequest();
                oReq.addEventListener("progress", updateProgress);
                oReq.addEventListener("load", transferComplete);
                oReq.addEventListener("error", transferFailed);
                oReq.addEventListener("abort", transferCanceled);

                oReq.open();

                // ...

                // progress on transfers from the server to the client (downloads)
                function updateProgress (oEvent) {
                  if (oEvent.lengthComputable) {
                    var percentComplete = oEvent.loaded / oEvent.total;
                    console.log(percentComplete+ " percent completed.");
                    // ...
                  } else {
                      console.log(" Unable to compute progress information since the total size is unknown.");
                    // Unable to compute progress information since the total size is unknown
                  }
                }

                function transferComplete(evt) {
                  console.log("The transfer is complete.");
                }

                function transferFailed(evt) {
                  console.log("An error occurred while transferring the file.");
                }

                function transferCanceled(evt) {
                  console.log("The transfer has been canceled by the user.");
                }

Actuall error is occuring on this line

oReq.open();

Answer 1

open() method has three parameters open('get' , url , true or false or null)