JS输出当前时间，且每秒变化

 <div id="timer"></div>
 <script type="text/javascript">
 window.setInterval(function(){
     var _date = new Date(); document.getElementById('timer').innerHTML = _date.toLocaleString() + ' 星期' + '日一二三四五六'.charAt(_date.getDay());
 }, 1000);
 </script>