2captcha solver for GM (based on https://addons.mozilla.org/en-US/firefox/addon/recaptcha-solver/)

2captcha.user.js

// ==UserScript==
// @name        recaptcha
// @namespace   *
// @include     *
// @version     1
// @grant       GM_xmlhttpRequest
// @grant       GM.xmlHttpRequest
// ==/UserScript==
// https://addons.mozilla.org/en-US/firefox/addon/recaptcha-solver/

var pageurl = window.location.href;
var messageError = "ERROR_WRONG_USER_KEY";
var messageNotReady = "CAPCHA_NOT_READY";
var id = "";
var message = document.createElement('span');
var button = document.createElement('button');
var afterElement = null;

function checkCompletion(code, key, repeat) {
	setupTextarea();
	//var http = new XMLHttpRequest();
	var url = 'https://2captcha.com/res.php?key='+key+'&action=get&id='+code+'&json=0';
	/*	http.onreadystatechange = function() {
		if(http.readyState == 4 && http.status == 200){
			var response = http.responseText;
			if(response == messageNotReady){
				setTimeout(function() {
					checkCompletion(code, key, repeat);
				}, repeat)
			}else{
				setCaptchaCode(response.substring(3));
			}
		}
	}
	http.open("GET", url, true);
	http.send(null);
	*/
	var options = {
	method: "GET",
	url: url,
	onload: function(res)
		{
			var response = res.responseText;
			if(response == messageNotReady)
			{
				sendMessage("waiting");
				setTimeout(function() {
						checkCompletion(code, key, repeat);
					}, repeat);
			}
			else
			{
				sendMessage("setting captha code");
				setCaptchaCode(response.substring(3));
			}
		}
	};
	try{
		GM.xmlHttpRequest(options);
	}
	catch(e)
	{
		GM_xmlhttpRequest(options);
	}
}

function getParameterByName(name, url) {
	if (!url) url = window.location.href;
	name = name.replace(/[\[\]]/g, "\\$&");
	var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
	results = regex.exec(url);
	if (!results) return null;
	if (!results[2]) return '';
	return decodeURIComponent(results[2].replace(/\+/g, " "));
}

function insertAfter(el, referenceNode) {
	referenceNode.parentNode.insertBefore(el, referenceNode.nextSibling);
}

function setCaptchaCode(code) {
	var ele = document.getElementById("g-recaptcha-response");
	sendMessage("<b>SOLVED</b>");
//	setChecked();
	if(ele != null){
		// uncomment this to show the textarea
		ele.style.display = "block";
		ele.innerHTML = code;
	}
	try{
	if(unsafeWindow.___grecaptcha_cfg.clients[0].ba.l.callback)
		unsafeWindow.___grecaptcha_cfg.clients[0].ba.l.callback(code);
	}
	catch(e)
	{
		sendMessage(e);
	}
}

function setupTextarea() {
	var ele = document.getElementById("g-recaptcha-response");
	if(ele != null){
		ele.style.display = "inline-block";
		ele.style.zIndex = "-1";
	}
}

function setupMessageBox() {
	message.innerHTML = "<b>prepared</b>";
	var container = document.createElement('div');
	container.className = '2captcha_solver';
	container.innerHTML = '';
	container.appendChild(message);
	button.innerHTML = 'solve';
	button.onclick = makeRequest;
	container.appendChild(button);
	container.style.backgroundColor = "#F9F9F9";
	container.style.border = "1px solid #D3D3D3";
	container.style.borderTop = "none";
	container.style.borderRadius = "0 0 3px 3px";
	container.style.padding = "5px";
	container.style.boxSizing = "border-box";
	container.style.width = "302px";
	container.style.margin = "-4px 2px 0 0";

	insertAfter(container, afterElement);
	// afterElement.appendChild(message);
}

function sendMessage(str){
	if( console )
		console.log(str);
	message.innerHTML = str;
}

function startWatching(code, key) {
	var initial = 15000, repeat = 5000;
	setTimeout(function() {
		try
		{
			checkCompletion(code, key, repeat);
		}
		catch(e)
		{
			alert(e);
		}
	}, initial);
}

function makeRequest(result){
	setupTextarea();
	sendMessage("<b>Solving captcha...</b>");
	var key = '<YOUR API KEY>';
	var url = 'https://2captcha.com/in.php?key='+key+'&googlekey='+id+'&method=userrecaptcha&soft_id=2151&pageurl='+pageurl;
	//var http = new XMLHttpRequest();
	/*http.onreadystatechange = function() {
		if(http.readyState == 4 && http.status == 200){
			var response = http.responseText;
			if(response == messageError){
				sendMessage("Error incorrect API key provided")
			}else{
				startWatching(response.substring(3), key);
			}
		}else if(http.readyState == 4){
			sendMessage("Error from 2captcha.com "+ http.status);
		}
	}
	http.open("GET", url, true);
	http.send(null);*/
	var options = {
	method: "GET",
	url: url,
	onload: function(res)
		{
			var response = res.responseText;
			if(response == messageError){
				sendMessage("Error incorrect API key provided");
			}else{
				startWatching(response.substring(3), key);
			}
		}
	};
	try{
		GM.xmlHttpRequest(options);
	}
	catch(e)
	{
		GM_xmlhttpRequest(options);
	}
	return false;
}



function postProcessPage2()
{
	// wait till id is visible
	var checkId = setInterval(function() {
		var ele = document.getElementsByClassName('g-recaptcha');
		if(ele != null && ele[0] != undefined){
			id = ele[0].getAttribute('data-sitekey');
			afterElement = ele[0].firstElementChild;
		}else{
			var frames = document.getElementsByTagName("iframe");
			for(var i = 0; i < frames.length; i++){
				var src = frames[i].getAttribute('src');
				if(src != null && src.startsWith("https://www.google.com/recaptcha")){
					id = getParameterByName("k", src);
					if(id != "" && id != null){
						afterElement = frames[i];
						break;
					}
				}
			}
		}
		if(id != "" && id != null){
			setupMessageBox();
			clearInterval(checkId);
		}
	}, 1000);
};

document.addEventListener('load', postProcessPage2, false);
postProcessPage2();