Open tab in background and get data from it - Chrome extension

Can someone can give me how to open an url in background and how can I get data from it. The URL that I want to open is in a page that also I get data from it. I use XPath to get data. This is my code :

Popup.js

chrome.tabs.query({
active: true, 
currentWindow: true }, function(tabs){
if(tabs[0].url.indexOf("extranet.louvre-hotels.fr")!=-1)
{
    chrome.tabs.sendRequest(tabs[0].id, {
        action: "getDOM"
    }, function(response)

    {   
        chrome.tabs.getSelected(null, function(tab) {
    // get response
        });         
    });
}

});

Manifest.json

{
"manifest_version": 2,

"name": "SymaExtract",
"description": "SymaExtract",
"version": "1.0",
"browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
},
"permissions": [
    "webNavigation",
    "tabs",
    "background",
    "http://localhost/extract.php",
    "http://*/*"

],
"background": {
    "scripts": ["background.js"]
},
"content_scripts": [
{
  "matches": ["http://*/*"],
  "js": ["dom.js"]
}

] }

Background.js

chrome.tabs.create({url: 'url_that_i_want_to_open'});