code: function variation(id) {
    var experiments = window._vwo_exp;
    if (!experiments) return null;
    var experiment = experiments[id];
    var variationId = experiment.combination_chosen;
    return variationId ? experiment.comb_n[variationId] : null;
  }
docs: Get the chosen variation's name from an experiment `id`.
  
  http://visualwebsiteoptimizer.com/knowledge/integration-of-vwo-with-kissmetrics/
  
  @param {String} id
  @return {String}