background.html

<script>
/*
 * Copyright (C) 2011 Thomas Dvornik
 * All rights reserved.
 *
 */

  chrome.browserAction.onClicked.addListener(function(tab) {
    chrome.tabs.sendRequest(tab.id, {browserAction: "clicked"}, function(response) {
      if (response.error == "load") {
        chrome.tabs.insertCSS(null, {
          file : "boxes.css"
        });
        chrome.tabs.executeScript(null, {
          file : "XPathBox.js"
        });
		chrome.tabs.executeScript(null, {
          file : "ElementContainer.js"
        });
        chrome.tabs.executeScript(null, {
          file : "main.js"
        });
      }
    });
  });

  chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
	if (request.att == 'get') {
      sendResponse({val: localStorage[request.param]});
  	}
  	else if (request.att == 'set') {
      localStorage[request.param] = request.val;
	  sendResponse({});
  	}
    else
      sendResponse({}); // snub them.
  });
</script>