popup.html

<style>
body {
  width: 150px;
}

li {
  margin-left: 0px;
  list-style-type: none;
}
</style>
<script>
onload = init;

var BackGround = chrome.extension.getBackgroundPage();
var Bob = BackGround.Bob;

function init() {
  var userInfo = Bob.getUserInfo();
  userInfo.forEach(function(data) {
    var item = document.createElement('input');
    item.type = 'radio';
    item.name = 'account';
    item.id = data.name;
    if (data.name == Bob.currentUser) item.checked = true;
    item.onclick = function() {
      chrome.cookies.get({ url: "http://www.hatena.ne.jp/", name: "rk"}, function(cookie) {
        Bob.changeCookie(cookie, data.rk);
        Bob.currentUser = data.name;
        Bob.reload();
      });
    }
    var li = document.createElement('li');
    li.appendChild(item);
    var label = document.createElement('label');
    label.setAttribute('for', data.name);
    label.textContent = data.name;
    li.appendChild(label);
    document.f.appendChild(li);
  });
}
</script>
<form name="f">
</form>