在页面设置时间

<span class="datetime" id="datetime">时间</span>
<span id="welcomeWord">问候语span> 

 

function setDateTime(){
  today=new Date();
  var day;
  var date;
  var hello;
  hour=today.getHours()
  if(hour < 6)hello='凌晨好!&nbsp;'
  else if(hour < 9)hello='早上好!&nbsp;'
  else if(hour < 12)hello='上午好!&nbsp;'
  else if(hour < 14)hello='中午好!&nbsp;'
  else if(hour < 17)hello='下午好!&nbsp;'
  else if(hour < 19)hello='傍晚好!&nbsp;'
  else if(hour < 22)hello='晚上好!&nbsp;'
  else {hello='半夜好!&nbsp;'}
  day=today.getDay()
  if(day==0)day='&nbsp;星期日'
  else if(day==1)day='&nbsp;星期一'
  else if(day==2)day='&nbsp;星期二'
  else if(day==3)day='&nbsp;星期三'
  else if(day==4)day='&nbsp;星期四'
  else if(day==5)day='&nbsp;星期五'
  else if(day==6)day='&nbsp;星期六'
  date=(today.getYear())+'年'+(today.getMonth()+1)+'月'+today.getDate()+'日';
  document.getElementById("welcomeWord").innerHTML = hello;
  document.getElementById("datetime").innerHTML = date + "&nbsp;&nbsp;&nbsp;&nbsp;" + day;
 }