server/www/screen.js

function Screen(modules) {
  var current = document.querySelector("body > div.on");
  var errorBox = document.getElementById('error');
  errorBox.addEventListener('click', function() {
    errorBox.className = "";
  });

  return {
    error: error,
    dialog: dialog,
    select: select
  };

  function select(name) {
    current.className = "";
    current = document.getElementById(name);
    current.className = "on";
  }

  function closeAndRun(dialog, action) {
    return function() {
      dialog.className = '';
      modules.dom.clear(dialog);
      action();
    };
  }

  function dialog(config) {
    var layer = document.getElementById('dialog');
    var dialog = modules.dom.make('div', {});
    dialog.appendChild(modules.dom.make('p', {textContent: config.text}));
    var answers = modules.dom.make('p', {class: 'answers'});
    for(var i in config.answers) {
      answers.appendChild(modules.dom.make('button', {
        textContent: modules.i18n.get(config.answers[i].label),
        onClick: closeAndRun(layer, config.answers[i].action)
      }));
    }
    dialog.appendChild(answers);
    layer.appendChild(dialog);
    layer.className = "on";
  }

  function error(message) {
    errorBox.textContent = message;
    errorBox.className = "on";
  }
}