Why is the alert repeated?

Question

JavaScript

I can not understand why when you click on the icon again, which calls the code below

chrome.browserAction.onClicked.addListener(function(tab) {
  chrome.tabs.executeScript({
    file: 'sc.js'
  });

 chrome.tabs.query({url: "http://google.ru/*", currentWindow: true}, function(tabs) {
var port = chrome.tabs.connect(tabs[0].id, {name: "knockknock"});
  port.postMessage({q: "ggh"});
})

 });

the alert is repeated, with each new click the alerts are added by one, the alert itself is written in executeScript below

chrome.runtime.onConnect.addListener(function(port) {
     port.onMessage.addListener(function(msg) {
  alert(msg.q)
  })
});

where should be cleaned?

Answer 1

Try wrapping the calls in a condition:
if (window.top !== window.self)