main.js

// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

var port = null;

function appendMessage(text) {
  //document.getElementById('response').innerHTML += "<p>" + text + "</p>";
}

function updateUiState() {
  if (port) {
    document.getElementById('connect-button').style.display = 'none';
    document.getElementById('input-text').style.display = 'block';
    document.getElementById('send-message-button').style.display = 'block';
  } else {
    document.getElementById('connect-button').style.display = 'block';
    document.getElementById('input-text').style.display = 'none';
    document.getElementById('send-message-button').style.display = 'none';
  }
}

function sendNativeMessage() {
  getCurrentTabUrl((url) => {
	message = url; //{"text": document.getElementById('input-text').value};
  console.log(url)
  console.log(port)
	port.postMessage(message);
	// appendMessage("Sent message: <b>" + JSON.stringify(message) + "</b>");
  })
  
}

function onNativeMessage(message) {
  appendMessage("Received message: <b>" + JSON.stringify(message) + "</b>");
  chrome.tabs.reload();
}

function onDisconnected() {
  appendMessage("Failed to connect: " + chrome.runtime.lastError.message);
  port = null;
  //updateUiState();
}

function connect() {
  var hostName = "com.google.chrome.example.echo";
  // appendMessage("Connecting to native messaging host <b>" + hostName + "</b>")
  port = chrome.runtime.connectNative(hostName);
  port.onMessage.addListener(onNativeMessage);
  port.onDisconnect.addListener(onDisconnected);
  // updateUiState();
}

function getCurrentIframeUrl(callback) {
    var iframe = document.getElementById('exampleIframe');
    iframe.src = chrome.extension.getURL('iframe-content-page.html');
    var url = iframe.src;
    callback(url);
  }

function getCurrentTabUrl(callback) {
  // Query filter to be passed to chrome.tabs.query - see
  // https://developer.chrome.com/extensions/tabs#method-query
  var queryInfo = {
    active: true,
    currentWindow: true
  };

  chrome.tabs.query(queryInfo, (tabs) => {
    // chrome.tabs.query invokes the callback with a list of tabs that match the
    // query. When the popup is opened, there is certainly a window and at least
    // one tab, so we can safely assume that |tabs| is a non-empty array.
    // A window can only have one active tab at a time, so the array consists of
    // exactly one tab.
    var tab = tabs[0];

    // A tab is a plain object that provides information about the tab.
    // See https://developer.chrome.com/extensions/tabs#type-Tab
    var url = tab.url;

    // tab.url is only available if the "activeTab" permission is declared.
    // If you want to see the URL of other tabs (e.g. after removing active:true
    // from |queryInfo|), then the "tabs" permission is required to see their
    // "url" properties.
    console.assert(typeof url == 'string', 'tab.url should be a string');

    callback(url);
  });

  // Most methods of the Chrome extension APIs are asynchronous. This means that
  // you CANNOT do something like this:
  //
  // var url;
  // chrome.tabs.query(queryInfo, (tabs) => {
  //   url = tabs[0].url;
  // });
  // alert(url); // Shows "undefined", because chrome.tabs.query is async.
}

document.addEventListener('DOMContentLoaded', function () {
  //document.getElementById('connect-button').addEventListener(
  //    'click', connect);
  //document.getElementById('send-message-button').addEventListener(
  //    'click', sendNativeMessage);
  
  connect()  
  sendNativeMessage()	
    
  // updateUiState();
});