Chrome extension background page html not working

I am trying to understand chrome background pages. I managed to get background.js script running after cannibalizing on the of examples and it pops up with an alert box every time a user visits a page. However, when I take the same script and move it to a background.html file, I cannot seem to get the file to execute.

I have updated the the manifest file to a page (instead of script) and the extension loads fine. I have also tried playing around with either having the javascript in a script tag directly in the body or in a function as it is now that is called onload on the body or in the head.

Perhaps I don't understand the concept of what a background.html page is used for in a Chrome extension?

Manifest file:

{
  "name": "Testing Extension",
  "version": "0.2",
  "background": { "pages": ["background.html"] },
  "permissions": [
    "tabs", "https://mail.google.com/*", "http://*/*, https://*/*"
  ],
  "browser_action": {
    "name": "Do some action",
    "icons": ["icon.png"]
  },
  "manifest_version": 2,
  "web_accessible_resources": ["injectImage.js", "background.html"]
}

injectImage.js

alert('Got Here');
'use strict';   
chrome.browserAction.onClicked.addListener(function (tab) {
    chrome.tabs.executeScript(null, {file: "injectImage.js"});
});

    chrome.browserAction.setBadgeBackgroundColor({color: [0, 200, 0, 100]});

    var i = 0;
    window.setInterval(function () {
        chrome.browserAction.setBadgeText({text: String(i)});
        i++;
    }, 10);

background.html

<!DOCTYPE html>
<html>
    <head>
        <script src="jquery-1.8.0.min.js"></script>
        <script src="injectImage.js"></script>
    </head>
    <body>
</body>
</html>

currently this code doesn't seem to do anything other than put an icon in the top right corner.