页面刷新问题！

<div id="dvContent" style="display:none"><input type="button" value="点击解锁"  onclick="check()"></div>
<script>  
  function ShowContent(show) {
    document.getElementById('dvContent').style.display = show ? 'block' : 'none';
  }
  function check() {
      document.cookie = 'unlock11';
      ShowContent(false);
  }
  window.onload = function () {
    if (document.cookie.indexOf('unlock11') == -1) ShowContent(true);
  }
</script>