Javascript OO and XMLHttpRequest

[Bodger2]

I am trying to organize a request/response ajax thingy here and have written this.

function myAJAXRequest (url, sendOutputTo)
{
this.url = url;
this.myRequest = new XMLHttpRequest ();
this.sendOutputTo = sendOutputTo;
this.myResponseDoc = null;

function processReqChange ()
{
var state = myRequest.readyState;

alert ("STATE (" + state + ")");

if (state == 4)
{
myResponseDoc = myRequest.responseXML.documentElement;
if (sendOutputTo != null)
{
sendOutputTo (myResponseDoc);
}
}
}

this.myRequest.onreadystatechange = this.processReqChange;
this.myRequest.open("GET", this.url, true);
this.myRequest.send("");
}

My method processReqChange never gets executed, much less can I track the state changes. I have been able to get this to work outside of the OO style. I am a little weak on Javascript OO and am trying to not have a custom processReqChange script for each of my requests.

Thanx

Bodger

 

[mbrooks]

No reason to 'reinvent the wheel' when there are plently of examples on the internet.

http://www.w3schools.com/dom/dom_http.asp

M. Brooks

http://mbrooks.info

 

[rac2]

processReqChange() must be a method of the myAJAXRequest object.

function myAJAXRequest () {

  ...

  this.processReqChange = function () {
    ...
  }

  ...

}

 

[Bodger2]

Thank you for your replies.

mbrooks - I need a little more power then is described there. I am having trouble understanding and working with the OO aspects of Javascript in regards to this.

rac2

>this.processReqChange = function

works, my processReqChange gets called, but it does not have its object context. How can I preserve the object context, specifically I am desperate to be able to contain the myRequest object in the processReqChange function.

Is there anyway to get the function to access the myAJAXRequest context? Specifically the myRequest object?

I do not want to build a custom processReqChange for each deployment.

Thanx

Bodger

 

[Bodger2]

I have solved my problem.

My primary requirement is to access my object from within the processReqChange function that is called by XMLHttpRequest so that I can manage functionalilty.

Here is my solution:


function myAJAXRequest (url, sendOutputTo)
{
myRequest = new XMLHttpRequest ();

this.url = url;
this.sendOutputTo = sendOutputTo;
this.myRequest = myRequest;

function myProcessReqChange ()
{
var myAJAX = this.myAjax;
var myRequest = myAJAX.myRequest;
var state = myAJAX.myRequest.readyState;
var sendOutputTo = myAJAX.sendOutputTo;

if (state == 4)
{
myResponseDoc = myRequest.responseXML.documentElement;
if (sendOutputTo != null)
{
sendOutputTo (myResponseDoc);
}
}
}

myProcessReqChange.myAjax = this;

myRequest.onreadystatechange = myProcessReqChange;
myRequest.open("GET", this.url, true);
myRequest.send("");
}

This is so cool, I was able to make my object a property of the function and then am able to access that property and hence the object from within the function. This is so cool.

Bodger