The code -

use strict;



var AJAX = function (params) {

    this.server ={};

    this.url = params.url;

    this.method = params.method;

    this.dataType = params.dataType;

    this.formData = params.formData;



    this.init = function(){

        if(typeof XMLHttpRequest != 'undefined'){

            this.server = new XMLHttpRequest();

            this.server.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');

            this.server.setRequestHeader('Content-length', this.formData.length);

            this.server.setRequestHeader('Connection', 'close');

            console.log(XMLHttpRequest created.);

            return true;

        }

    };



    this.send = function(){

        if(this.init()){

            this.server.open(this.method, this.url, true);

            this.server.send(this.formData);

        }

    };



};

It is throwing following error :

Error in event handler for contextMenus: InvalidStateError: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': The object's state must be OPENED.

How it's being used -

var data = new FormData();



data.append('user', 'sachin');

var params = {

    url : 'example.com',

    method : 'post',

    dataType: 'json',

    formData : data

};



var backgroundWindow = chrome.extension.getBackgroundPage();



var ajax = new backgroundWindow.AJAX(params);



ajax.send();

I can't seem to figure out what's the reason behind.