How do you intercept the server's response in XMLHtpRequest?

[Mystic]

Is it possible to change XMLHtpRequest so that the contents of the response can be intercepted without replacing the entire object with all its methods?
It is expected that there will be challenges in the code like:

x = new XMLHttpRequest();
x.open( "GET", "/" );
x.onreadystatechange = function () {...};
x.send( null );

or even one-point:

x = new XMLHttpRequest();
x.open( "GET", "/" );
x.send( null );
x.onreadystatechange = function () {...};

[Amritpal]

Decision for Blink

Blink is Chrome, Opera etc.

Prototype XMLHttpRequest onreadystatechange as a ghetter/netter and assuring its ghetter/netter, the logic of work should not be broken. XMLHttpRequest:

var oldXMLHttpRequest = XMLHttpRequest;
XMLHttpRequest = function() {

var xhr = new oldXMLHttpRequest();

// получаем дескриптор прототипных setter/getter

var descrGetSet = Object.getOwnPropertyDescriptor(

Object.getPrototypeOf( xhr ),

"onreadystatechange" );
var newSet = function( val ) {
    console.log ( "setter" );
    descrGetSet.set.call( xhr, function() { // прототипный setter
         console.log( "Inject "+this.status ); // this.responseText
         return val.apply( xhr, arguments );
    } );
}

Object.defineProperty( xhr, "onreadystatechange", {

set: newSet, // новый setter

get: descrGetSet.get // старый getter

} );
return xhr;

}

Now make:

x = new XMLHttpRequest();

x.open( "GET", "/" );

x.send( null )

x.onreadystatechange = function () { console.log( this.statusText+' is 2' )};

See.

Inject 200

OK is 2

Inject 200

OK is 2

Inject 200

OK is 2

Which should be when you change. readyState♪

---

Decision for Webkit

Webkit - Safari, PhantomJS

The problem is this move-- onreadystatechange It's a ghetter. XHRNot XHR.prototype♪ You can't redesign it. Learn from XHR You can't, too, so you need to use a vest. XHR♪
It's very good.
https://github.com/ilinsky/xmlhttprequest