<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<!--CSS樣式-->
<style type="text/css">
*{margin: 0px;padding: 0px;}
#div{width: 400px;height: 300px;border: 1px solid red;margin: auto;}
#div div:nth-child(1){display: flex;align-items: center;justify-content: center;}
#tbcal{border-collapse: collapse;width: 100%;text-align: center;}
#tbcal tr td{border: 1px solid red;}
</style>
<script type="text/javascript">
// 顯示日曆
</script>
</head>
<body>
<div id="div">
<!--定義年月菜單-->
<div>
<select id="selyear">
<option selected>2020</option>
</select> 年
<select id="selmonth">
<option selected>1</option>
<option selected>2</option>
<option selected>3</option>
<option selected>4</option>
<option selected>5</option>
<option selected>6</option>
<option selected>7</option>
<option selected>8</option>
</select> 月
</div>
<div>
<!--定義列表-->
<table id="tbcal">
<tr>
<td>週日</td>
<td>週一</td>
<td>週二</td>
<td>週三</td>
<td>週四</td>
<td>週五</td>
<td>週六</td>
</tr>
</table>
</div>
</div>
</body>
</html>
<script type="text/javascript">
show();
document.getElementById("selmonth").onchange = show;
function show(){
// 獲取鼠標點擊所選擇的年月值
var year=parseInt(document.getElementById("selyear").value);
var month=parseInt(document.getElementById("selmonth").value);
// 判斷是否爲閏年,以便確定2月的天數
var flag=year%4==0&&year%100!=0||year%400==0;
var dayofmonth=[31,flag?29:28,31,30,31,30,31,31,30,31,30,31];
// 給date賦值,值爲所選擇的某年某月一號
var dt=new Date();
dt.setFullYear(year);
dt.setMonth(month-1);
dt.setDate(1);
// 獲取date對應周幾
var week=dt.getDay();
// 當月應該打印多少行
var rows=Math.ceil((dayofmonth[dt.getMonth()]+week)/7);
console.log(rows);
var k=0;
// 如果表格中有除表頭外的數據,進行數據刪除,避免上次月份的數據對下次有影響
var table=document.getElementById("tbcal");
while(table.rows.length>1){
table.deleteRow(1);
}
// 循環向表格中添加數據，生成日曆
for(var i=0;i<rows;i++){
var row=table.insertRow(i+1);
for(var j=0;j<7;j++){
var cell=row.insertCell(j);
k++;
if(k<=week || k>dayofmonth[dt.getMonth()]+week){
cell.innerHTML="";
}
else{
cell.innerHTML=k-week;
}
}
}
}
</script>
