Get a JSON structure with all your open tabs

gistfile1.js

// Needs to be run in the context of an extension with the "tabs" permission.

chrome.tabs.query({}, function(tabs) { 
  var byWindow = {}; 
  tabs.forEach(function(t) { 
    if(!byWindow[t.windowId]) { 
      byWindow[t.windowId] = [] 
    }
    byWindow[t.windowId].push(t.url); 
    console.log(JSON.stringify(byWindow, null, 2)); 
  });
});