xmlHttpRequest to absolute url in WP8 - windows-phone-8

Question

I have stumbled across an odd issue when testing an app in Windows Phone 8. I am using xmlHttpRequest (cannot use ajax as I need to send as bufferarray) to make a call to a third party url. This works perfectly in Android and iOS, but throws an error in WP8
Example:
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function (){
if(xhr.readyState == 4){
if(xhr.status==200){
alert(xhr.responseText);
}else{
console.log("Error: "+xhr.responseText);
}
}
}
console.log("1");
xhr.timeout = 30000;
console.log("2");
xhr.open("POST","http://google.com",true);
console.log("3");
xhr.setRequestHeader("Content-Type",contentType+"; boundary=" + boundary);
console.log("4");
//other headers / auth etc
console.log("about to post");
xhr.send(bodyBuf);
this will result in:
log:"before request"
log:"1"
log:"2"
log:"Error in error callback: Cameraxxxxx = InvalidStateError"
However if I chang the open to:
xhr.open("POST","google.com",true); //or www.google.com etc
This goes right through to send, but then get a 404 status as the url is not found. I am obviously not using google in my request, but the error is the same. With "http://" it errors, but without, it doesn't error but cannot find the url.
Any thoughts appreciated.
I have found one thing, but unsure if it is related. According to W3C html 5 documentation, InvalidStateError is thown on open() if document is not fully active (when it is the active document of its browsing context). And if this is the cause of the error; how can the document not be the active document and how to I define the base url of an app that does not reside on a url (document suggests setting base to the document base url of document (or setting source origin/referrer source))?
Have gotten one step closer. After lots of fiddling about, I eventually found that for some reason on WP8 is needs the xhr to be opened before anything else is applied. So moving xhr.timeout below xhr.open sort of works.
this raises another problem in my particular case.. but that is probably another topic.

Answer 1

Solution for this was to move the timout to below the open.. so:
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function (){
if(xhr.readyState == 4){
if(xhr.status==200){
alert(xhr.responseText);
}else{
console.log("Error: "+xhr.responseText);
}
}
}
xhr.open("POST","http://google.com",true);
xhr.timeout = 30000;
xhr.setRequestHeader("Content-Type",contentType+"; boundary=" + boundary);
//other headers / auth etc
xhr.send(bodyBuf);