Pure js simulates windows system calendar
- 2021-07-16 01:15:42
- OfStack
I read several js tutorials about generating calendars on the Internet, so I also sorted out an idea. What suggestions do you have? Welcome to put forward
First of all, I think several difficulties in this project:
1. How to define the position on the first day of every month
The first day of each month is not a fixed day of the week, so the output of the first day needs to be put into the corresponding week
2. What should I do on the last day of each month because there are not enough lines to output?
There will be an answer below _ ^
Thoughts:
1. Define the date and number of days every 1 month
2. Get the current system date initialization data
3. Output calendar
2.1. Get the day of the week on the first day of the current month (this 1 point is very important to the layout of the calendar!)
2.2. Get the number of days in the current month
2.3. Get how many weeks there are in the current month (that is, how many lines to output here I will reserve one more line)
2.4. Get the current year and month for display
Here's the complete code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>js 日历</title>
<style type="text/css">
*{
border: 0;
padding: 0;
margin: 0;
font-family: "微软雅黑";
}
a{
text-decoration: none;
color: #000;
}
li{
list-style-type: none;
}
.calendar_wrap{
width: 350px;
margin: 0 auto;
padding: 0;
border: 1px solid #000;
}
.calendar_list{
width: 100%;
margin-top: 10px;
}
.calendar_list tr{
width: 100%;
}
.calendar_list tr td{
text-align: center;
height: 45px;
}
.control_bar{
word-spacing: -6px;
}
.control_bar span,.control_bar b{
display: inline-block;
text-align: center;
word-spacing: 0px;
}
.left-bt,.right-bt{
width: 50px;
}
#reduce_bt,#add_bt{
width: 50%;
height: 25px;
border-radius: 50%;
}
#reduce_bt:focus{
outline: none;
}
#add_bt:focus{
outline: none;
}
#current_date{
width: 250px;
}
#resetBt{
display: block;
text-align: center;
color: #fff;
cursor: pointer;
width: 120px;
line-height: 40px;
background-color: #FF7F27;
margin: 0 auto;
}
#date_list tr td:hover{
background-color: #ccc;
cursor: default;
}
</style>
</head>
<body>
<div class="calendar_wrap">
<div class="control_bar">
<span class="left-bt"><input type="button" id="reduce_bt" value="<"></span>
<b id="current_date">2017-02</b>
<span class="right-bt"><input type="button" id="add_bt" value=">"></span>
</div>
<table class="calendar_list" cellspacing="0">
<thead>
<tr>
<td>日</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>4</td>
<td>5</td>
<td>6</td>
</tr>
</thead>
<tbody id="date_list"></tbody>
</table>
</div>
<span id="resetBt">回到现在日期</span>
<script type="text/javascript">
var dateScreen = document.getElementById('current_date');//获取显示当前年份月份的div
var reduceBt = document.getElementById('reduce_bt');//获取减少月份的按钮
var addBt = document.getElementById('add_bt');//获取增加月份的按钮
var dateList = document.getElementById('date_list');//获取显示所有日期部分
var resetBt = document.getElementById('resetBt');//获取重设按钮
//定义好每月的日期总数 总数按js 获取月份数值的下标方式储存
var overall_date = [31,28,31,30,31,30,31,31,30,31,30,31];
var add_date = 1;//定义添加日期数的初始化
//初始化日历
//获取现在的日期
var now_date = new Date();
var nowFullYear = now_date.getFullYear();
var nowMonth = now_date.getMonth();
//执行日历输出函数
printCalendar();
//-----------------------------------
//月份减少按钮点击事件
reduceBt.onclick = function(){
nowMonth = nowMonth - 1;
if (nowMonth == -1) {
nowFullYear = nowFullYear - 1;
nowMonth = 11;
}
clearRows();
printCalendar();
}
//增加月份按钮点击事件
addBt.onclick = function(){
nowMonth+= 1;
if (nowMonth == 12) {
nowFullYear+= 1;
nowMonth = 0;
}
clearRows();
printCalendar();
}
//重设按钮点击事件
resetBt.onclick = function(){
var resetDate = new Date();
nowFullYear = resetDate.getFullYear();
nowMonth = resetDate.getMonth();
clearRows();
printCalendar();
}
function printCalendar(){
var printDate = new cur_date(nowFullYear,nowMonth);//实例cur_date方法
var printFirstDay = printDate.firstDay;//获取要输出月份第1天的星期
var printTotalDate = printDate.totalDate;//获取输出日期的总数
var printMonth = printDate.cur_month;//获取输出的月份
(printMonth >= 9)?(printMonth = (printMonth + 1)):(printMonth = ("0" + (printMonth + 1)));
//调整月份的显示格式
var printYear = printDate.cur_year;//获取输出的年份
var totalRows = Math.ceil((printTotalDate + (printFirstDay - 1)) / 7) + 1;
//获取行数
//利用天数除以7天获得行数并将它向上去整 但是上限是5
//而考虑到某些月会有6行所以在总行数里面加1 以防万1
//开始输出
//首先显示出年和月
dateScreen.innerText = printYear + "-" + printMonth;
//开始输出日期
for (var i = 0; i < totalRows; i++) {
dateList.insertRow(i);
for (var j = 0; j < 7; j++) {
//当天数总量大于额定总量时先终止内部循环
if (add_date > printTotalDate) {
break;
}
dateList.rows[i].insertCell(j);
//改变周日和周6的文字颜色
if (j == 0) {
dateList.rows[i].cells[j].style.color = "red";
dateList.rows[i].cells[j].style.fontWeight = "bold";
}else if(j == 6){
dateList.rows[i].cells[j].style.color = "green";
dateList.rows[i].cells[j].style.fontWeight = "bold";
}
if (i == 0 && j >= printFirstDay) {
//当此时是第1行时而且单元格下标大于等于当前月第1天的星期就开始为单元格填入文本
dateList.rows[i].cells[j].innerText = add_date;
add_date++;
}else if(i > 0){
//第1行以后的单元格就按循环添加即可
dateList.rows[i].cells[j].innerText = add_date;
add_date++;
}
}
}
add_date = 1;//输出完把日期总数重新赋值为1
}
//获取当前年、月、第1天是星期几、日期总数
function cur_date(curYear,curMonth){
this.cur_firstDate = new Date(curYear,curMonth,1);//获取现在日期的第1天
this.cur_year = curYear;//获取当前的年
this.cur_month = curMonth;//获取当前的月
this.totalDate = is_leapYear(curYear,curMonth);//获取总天数
this.firstDay = this.cur_firstDate.getDay()//获取每个月的第1天是星期几
}
//判断今年是否为闰年
function is_leapYear(target_year,target_month){
if ((target_month == 1) && (target_year % 4 == 0) && ((target_year % 100 != 0) || (target_year % 400 != 0))) {
//当前月是2月且当前年是闰年
return 29;
}else{
//其他月按正常日期总数输出
return overall_date[target_month];
}
}
function clearRows(){
var rowsNum = dateList.rows.length;
while(rowsNum > 0){
dateList.deleteRow(rowsNum - 1);
rowsNum--;
}
}
</script>
</body>
</html>