Native js implements date linkage_javascript skills

Month determination involves too many determination conditions. Using if else will greatly reduce performance. It is recommended to use switch syntax

The code is as follows:

Copy code The code is as follows:

getDays:function(year,month){
// var aDay = [31,28|29,31,30,31,30,31,31,30,31,30,31];
// Day data processing in February
      var FedDays = year%4==0?29:28,
             returnDays = '';
        var month = month<10?month = '0' month:month.toString();
switch(month){
case '01':
case '03':
case '05':
case '07':
case '08':
case '10':
case '12': returnDays = 31;break;
case '04':
case '06':
case '09':
case '11': returnDays = 30;break;
case '02': returnDays = FedDays;break;
}
         return returnDays;
}

Full source code:

Copy code The code is as follows:

/* author:laoguoyong
----------------------------------
Date three-level linkage, range selection
----------------------------------
Parameters
* [String] targets:'#year,#month,#day'; id of year, month and day
* [String] range:'2013-02-03,2019-09-21'; range, the correct format is xxxx-xx-xx
----To save code, please pass in the correct date range parameter
----Error demonstration:
(1) range:'2013-02-03,2019-9-21' is incorrect, pay attention to the date format
(2) range:'2013-02-03' is incorrect, please enter the complete range value
(3) range:'2013-02-03,2016-02-30' is wrong, February does not have 30 days
(3) range:'2013-02-03,2011-02-30' is incorrect, the range is wrong
*
*/
function GySetDate(opt){
//elem
var targets = opt.targets.split(',');
This.eYear = this.getId(targets[0].slice(1));
This.eMonth = this.getId(targets[1].slice(1));
This.eDay = this.getId(targets[2].slice(1));
If(!this.eYear||!this.eMonth||!this.eDay) return;
//Range value
var r = opt.range.indexOf(','),
aStarts = opt.range.slice(0,r).split('-'), // Convert to: ['2013','05','20']
aEnds = opt.range.slice(r 1,opt.range.length).split('-'); // Convert to: ['2018','08','20']
//Number type
This.startYear = parseInt(aStarts[0],10);
This.startMonth = parseInt(aStarts[1],10);
This.startDay = parseInt(aStarts[2],10);
This.endYear = parseInt(aEnds[0],10);
This.endMonth = parseInt(aEnds[1],10);
This.endDay = parseInt(aEnds[2],10);

    this.init();
}
GySetDate.prototype = {
    init:function(){
        var _that = this;
        // 初始化日期
        this.setYears({'start':this.startYear,'end':this.endYear});
        this.setMonths({'start':this.startMonth});
        this.setDays({'year':this.startYear,'month':this.startMonth,'start':this.startDay});
        // 年选择
        this.eYear.onchange = function(){
            var year = parseInt(this.value);
            switch(true){
                case (year == _that.startYear):{
                    _that.setMonths({'start':_that.startMonth});
                    _that.setDays({'year':_that.startYear,'month':_that.startMonth,'start':_that.startDay});
                };break;
                case (year == _that.endYear):{
                    _that.setMonths({'start':1,'end':_that.endMonth});
                    if(_that.endMonth>1){
                        _that.setDays({'year':_that.endYear,'month':1,'start':1});   
                    }else{
                        _that.setDays({'year':_that.endYear,'month':1,'start':1,'end':_that.endDay});
                    }
                };break;
                default:{
                    _that.setMonths({'start':1});
                    _that.setDays({'start':1,'year':year,'month':1});
                }
            }
           
        }
        // 月选择
        this.eMonth.onchange = function(){
            var year = parseInt(_that.eYear.options[_that.eYear.selectedIndex].value),
                month = parseInt(this.value);
            switch(true){
                case (year==_that.endYear&&month==_that.endMonth):{
                    _that.setDays({'start':1,'year':year,'month':month,'end':_that.endDay});
                };break;
                case (year==_that.startYear&&month==_that.startMonth):{
                    _that.setDays({'year':_that.startYear,'month':_that.startMonth,'start':_that.startDay});
                };break;
                                                                                                                                                                                                                                                           default:{
                        _that.setDays({'start':1,'year':year,'month':month});
                }
                                                                                                                                             }
},
/*Set year, month, day
​​---------------------------------
The parameter values ​​are all of type Number
*/
// Parameters {'start':xx,'end':xxx}
setYears:function(opt){
This.eYear.innerHTML = '';
for(var n=opt.start;n<=opt.end;n ){
This.eYear.add(new Option(n,n));
}
},
// Parameters {'start':xx,'end':xxx}
//The parameter 'end' is optional, if ignored, it will start to December
setMonths:function(opt){
This.eMonth.innerHTML = '';
var months = opt.end || 12;
for(var n=opt.start;n<=months;n ){
If(n<10) n = '0' n;
This.eMonth.add(new Option(n,n));
}
},
// Parameters {'start':xx,'year':xxx,'month':xx,'star':xx,'end':xxx}
//The parameter 'end' is optional, if ignored, it will start to the end of this month (judged based on the month)
setDays:function(opt){
This.eDay.innerHTML = '';
        var days = opt.end || this.getDays(opt.year,opt.month);
for(var n=opt.start;n<=days;n ){
If(n<10) n = '0' n;
This.eDay.add(new Option(n,n));
         }
},
/* Based on the year and month, return the correct number of days, such as 2016-2, the return is 29 days (run year)
-------------------------------------------------- ------------
The parameter values ​​are all of type Number
*/
GetDays:function(year,month){
// var aDay = [31,28|29,31,30,31,30,31,31,30,31,30,31];
// Day data processing in February
      var FedDays = year%4==0?29:28,
             returnDays = '';
        var month = month<10?month = '0' month:month.toString();
switch(month){
case '01':
case '03':
case '05':
case '07':
case '08':
case '10':
case '12': returnDays = 31;break;
case '04':
case '06':
case '09':
case '11': returnDays = 30;break;
case '02': returnDays = FedDays;break;
}
         return returnDays;
},
/*Tool auxiliary function
​​---------------------------------
*/
GetId:function(id){
           return document.getElementById(id);
}
}

Effect display:

The effect is not bad, friends, you can beautify it and use it in your own projects.