How to communicate between popup.js and background.js in chrome extension?
JavascriptGoogle Chrome-ExtensionJavascript Problem Overview
The message from popup.js is being posted twice to background.js, but I get absolutely nothing from background.js.
background.js
function login(username,password){
console.log(username);
var xhr = new XMLHttpRequest();
xhr.open("POST", "http://localhost:3000/login/", true);
xhr.setRequestHeader('Content-type','application/json; charset=utf-8');
data = {"username":username,"password":password};
console.log(JSON.stringify(data));
xhr.send(JSON.stringify(data));
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
// JSON.parse does not evaluate the attacker's scripts.
var resp = JSON.parse(xhr.responseText);
console.log(resp);
var lStorage = localStorage;
localStorage.setItem("username",resp["username"]);
localStorage.setItem("apiKey",resp["apiKey"]);
localStorage.setItem("password",resp["password"]);
console.log(localStorage.getItem("username"));
}
};
}
chrome.extension.onRequest.addListener(
function(request, sender, sendResponse){
console.log("hello");
if(request.msg == "login") {
//alert(request.password);
login(request.username,request.password);}
}
);
chrome.extension.onConnect.addListener(function(port) {
console.log("Connected .....");
port.onMessage.addListener(function(msg) {
console.log("message recieved "+ msg);
port.postMessage("Hi Popup.js");
});
});
popup.js:
function login(){
alert(document.login.username.value);
chrome.extension.sendRequest({ msg: "login",username:document.login.username.value,password:document.login.password.value});
document.getElementById('openBackgroundWindow').visbility = "hidden";
}
$(document).ready(function (){
checkUserAuth();
console.log("Inside");
$("#openBackgroundWindow").click(login);
});
function checkUserAuth(){
console.log(localStorage.getItem("apiKey"));
if(localStorage.getItem("apiKey") != null)
{
$("#openBackgroundWindow").visbility ="hidden";
}
}
var port = chrome.extension.connect({name: "Sample Communication"});
port.postMessage("Hi BackGround");
port.onMessage.addListener(function(msg) {
console.log("message recieved"+ msg);
});
Javascript Solutions
Solution 1 - Javascript
Method - A :
Using Long Lived Connections you can communicate from background.js to popup.js of extension page for any activities( Here i have included popup.html and only initiated sample communication from popup.js as a sample)
background.js
chrome.extension.onConnect.addListener(function(port) {
console.log("Connected .....");
port.onMessage.addListener(function(msg) {
console.log("message recieved" + msg);
port.postMessage("Hi Popup.js");
});
})
popup.js
var port = chrome.extension.connect({
name: "Sample Communication"
});
port.postMessage("Hi BackGround");
port.onMessage.addListener(function(msg) {
console.log("message recieved" + msg);
});
Method - B :
Direct Manipulation of DOM* if your end result is modification of DOM, you can achieve with this
popup.html
<html>
<head>
<script src="popup.js"></script>
</head>
<body>
<div id="x" value="m">Some thing</div>
</body>
</html>
background.js
var views = chrome.extension.getViews({
type: "popup"
});
for (var i = 0; i < views.length; i++) {
views[i].document.getElementById('x').innerHTML = "My Custom Value";
}
Method - C :
Using Long Lived Connections you can communicate from background.js to popup.js of extension page for any activities( Here i have not included popup.html and initiated sample communication from background.js;
background.js
chrome.browserAction.onClicked.addListener(function(tab) {
var port = chrome.extension.connect({
name: "Sample Communication"
});
port.postMessage("Hi BackGround");
port.onMessage.addListener(function(msg) {
console.log("message recieved" + msg);
});
});
I have changed your code and made it running after eliminating some stuff and making it a simple version. Add your code for AJAX requests and HTML DOM on this skeleton( Make sure you add <script> tag in head section and put chrome.extension.onConnect.addListener out of (xhr.readyState == 4) code;)
popup.html
<html >
<head>
<script src="popup.js"></script>
</head>
<body></body>
</html>
manifest.json
{
"name": "Demo",
"version": "1.0",
"manifest_version": 2,
"description": "This is a demo",
"browser_action": {
"default_popup": "popup.html"
},
"background": {
"scripts": ["background.js"]
},
"permissions": ["<all_urls>",
"storage",
"tabs"
]
}
background.js
chrome.extension.onConnect.addListener(function(port) {
console.log("Connected .....");
port.onMessage.addListener(function(msg) {
console.log("message recieved " + msg);
port.postMessage("Hi Popup.js");
});
});
popup.js
var port = chrome.extension.connect({
name: "Sample Communication"
});
port.postMessage("Hi BackGround");
port.onMessage.addListener(function(msg) {
console.log("message recieved" + msg);
});
Solution 2 - Javascript
This can be used in 2 way communication. Same code goes in both the files.
popup.js & background.js
//for sending a message
chrome.runtime.sendMessage({greeting: "hello"}, function(response) {
});
//for listening any message which comes from runtime
chrome.runtime.onMessage.addListener(messageReceived);
function messageReceived(msg) {
// Do your work here
}
Ref: https://developer.chrome.com/extensions/runtime#method-sendMessage
Solution 3 - Javascript
Full Duplex Communication
Call background.js methods asynchronously from popup.js and get response back:
Popup.js:
// wrapper method
function getContent() {
callEventPageMethod('getContent', 'some parameter', function (response) {
doSomethingWith(response);
});
}
//generic method
function callEventPageMethod(method, data, callback) {
chrome.runtime.sendMessage({ method: method, data: data }, function (response) {
if(typeof callback === "function") callback(response);
});
}
Background.js/eventPage.js:
chrome.runtime.onMessage.addListener(callback);
function callback(obj, sender, sendResponse) {
if (obj) {
if (obj.method == 'getContent') {
getContent(sendResponse);
} else if (obj.method == 'othermethod') {
}
}
return true; // remove this line to make the call sync!
}
//some async method
function getContent(sendResponse) {
chrome.storage.local.get(["mydata"], function (obj) {
var mydata = $.trim(obj["mydata"]);
sendResponse(mydata);
});
}
If need to call popup.js methods from background.js then swap the above code in files.
Method 2: You can load the reference of background page in a variable and access all methods.
var bgPage = chrome.extension.getBackgroundPage();
var response = bgPage.someMethodInBGPage();