<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
td {
text-align: center;
}
</style>
</head>
<body>
<p>
<select id="yearSelect"></select>
<select id="monthSelect"></select>
<strong></strong>
</p>
<table id="tab" width="100%" border="1">
<thead>
<tr>
<th>日</th>
<th>一</th>
<th>二</th>
<th>三</th>
<th>四</th>
<th>五</th>
<th>六</th>
</tr>
</thead>
<tbody></tbody>
</table>
<script>
/*
* 获取指定年月份的日期总天数
* 显示的月份的第一天是星期几？
* */
var yearSelectElement = document.querySelector('#yearSelect');
var monthSelectElement = document.querySelector('#monthSelect');
var tbody = document.querySelector('tbody');
var strongElement = document.querySelector('strong');
var nowDate = new Date();
/*
* 动态生成option
* */
var html = '';
for (var i=1970; i<2100; i++) {
if (i == nowDate.getFullYear()) {
html = '<option selected>'+ i +'</option>' + html;
} else {
html = '<option>'+ i +'</option>' + html;
}
}
yearSelectElement.innerHTML = html;
var html = '';
for (var i=0; i<12; i++) {
if (i == nowDate.getMonth()) {
html += '<option value="'+i+'" selected>'+ (i+1) +'</option>';
} else {
html += '<option value="'+i+'">'+ (i+1) +'</option>';
}
}
monthSelectElement.innerHTML = html;
/*
* 默认显示当前年和月的日历
* */
calendar(nowDate.getFullYear(), nowDate.getMonth());
/*
* 根据选择的年和月重新生成日历
* */
yearSelectElement.onchange = monthSelectElement.onchange = function() {
calendar(yearSelectElement.value, monthSelectElement.value);
};
function calendar(year, month) {
year = Number(year);
month = Number(month);
strongElement.innerHTML = year + '年' + (month+1) + '月';
var html = '<tr>';
for (var i=1; i<=42; i++) {
if (i%7 == 1 && i != 1) {
html += '</tr><tr>';
}
var v = i- getFirstDay(year, month);
if (v < 1 || v > getDays(year, month)) {
html += '<td> </td>';
} else {
if (i % 7 == 1 || i % 7 == 0) {
html += '<td style="color: red">'+ v +'</td>';
} else if (
year == nowDate.getFullYear()
&&
month == nowDate.getMonth()
&&
v == nowDate.getDate()
) {
html += '<td style="background: red; color:white;">'+ v +'</td>';
} else {
html += '<td>'+ v +'</td>';
}
}
}
html += '</tr>';
tbody.innerHTML = html;
}
/*
* 获取指定显示年月份的日期总天数
* */
function getDays(y, m) {
return new Date(y, m+1, 1, -1, 0, 0).getDate();
/*
* 得到下一月的1日，-1时0分0秒的日期
* -1 ： 其实就是前一天，表示就是上个月的最后一天的23时
* */
var date = new Date(y, m+1, 1, -1, 0, 0);
/*
* 上个月最后一天的日期其实就是上个月总的天数
* */
return date.getDate();
}
/*
* 获取指定显示的年月份的第一天是星期几
* */
function getFirstDay(y, m) {
return new Date(y, m, 1).getDay();
}
</script>
</body>
</html>