Google analytics 谷歌内容实验不会选择一种变体

我有以下脚本：

<script src="//www.google-analytics.com/cx/api.js?experiment=XXXXXXXXXXXXXXXXXXXXXXX"></script>
<script>

  // Determine the current chosen variation
  console.log( cxApi.getChosenVariation() ); // returns -1 (equivalent to cxApi.NO_CHOSEN_VARIATION)

  // Tell Google to choose a variation for me
  var variation = cxApi.chooseVariation();
  console.log( variation );  // returns 0  <-- original variation

  // Determine current chosen variation again
  console.log( cxApi.getChosenVariation() ); // returns -1 again... why?

  // Lets force a chosen variation:
  variation = cxApi.setChosenVariation(1);

  // And determine the chosen variation one more time:
  console.log( variation ); // returns 1, as expected

</script>

//确定当前选择的变化
console.log（cxApi.getChosenVariation（））；//返回-1（相当于cxApi。未选择任何变量）
//告诉谷歌为我选择一个变体
var variation=cxApi.chooseVariation（）；
console.log（变体）；//返回0解决方案在这里解决方案在这里