popup.js

debugger;
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
    chrome.browserAction.getTitle({tabId: tabs[0].id}, function(result) {
        console.log( tabId + "==Browser action title==", result);
    });
});

function click(e) {
  // console.log(e.target);
  chrome.tabs.executeScript(null, {
    code:"document.body.style.backgroundColor='" + e.target.className + "'"
  });
  window.close();
}

document.addEventListener('DOMContentLoaded', function () {
  var li = document.querySelectorAll('li');
  for (var i = 0; i < li.length; i++) {
    li[i].addEventListener('click', click);
  }
});