added short comments for all JS functions

open-my-page-button/background.js

@@ -1,5 +1,11 @@
+ /*
+ Add openMyPage() as a listener to clicks on the browser action.
+ */
  chrome.browserAction.onClicked.addListener(openMyPage);
  
+ /*
+ Open a new tab, and load "my-page.html" into it.
+ */
  function openMyPage() {
    console.log("injecting");
     chrome.tabs.create({