原文来自：https://www.jb51.net/article/108852.htm
<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>日历操作</title>
<script>
window.onload = function(){
var cells = document.getElementById('monitor').getElementsByTagName('td');
var clen = cells.length;
var currentFirstDate;
var formatDate = function(date){
var year = date.getFullYear()+'年';
var month = (date.getMonth()+1)+'月';
var day = date.getDate()+'日';
var week = '('+['星期天','星期一','星期二','星期三','星期四','星期五','星期六'][date.getDay()]+')';
return year+month+day+' '+week;
};
var addDate= function(date,n){
date.setDate(date.getDate()+n);
return date;
};
var setDate = function(date){
var week = date.getDay()-1;
date = addDate(date,week*-1);
currentFirstDate = new Date(date);
for(var i = 0;i<clen;i++){
cells[i].innerHTML = formatDate(i==0 ? date : addDate(date,1));
}
};
document.getElementById('last-week').onclick = function(){
setDate(addDate(currentFirstDate,-7));
};
document.getElementById('next-week').onclick = function(){
setDate(addDate(currentFirstDate,7));
};
setDate(new Date());
}
</script>
</head>
<body>
<button id="last-week">上一周</button><button id="next-week">下一周</button>
<table id="monitor">
<tr>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
</table>
</body>
</html>