Just made a date addition and subtraction to prevent later use. Make a small record first

I met two small problems during the whole process (1. I confused the Date of Day acquisition with the Day of week acquisition, 2. I met NaN in judgment)

1.false, null, 0, "", undefined are all easy to judge. Use = = = directly
But NaN can't use = = =

> NaN === NaN;
false  //Always return false

2. There is a global function isNaN() in JS, but there is a problem with this function. It always implicitly converts the value in the parameter into a number and then makes a judgment. In this way, it returns true when judging many obviously non NaN values:

> isNaN("foo") 
true 

resolvent:

     

function myIsNaN(value) { 
    return value !== value; 
} 
//Before using isNaN(), check whether the value is a numeric type, so as to avoid the problem of implicit conversion:

function myIsNaN2(value) { 
    return typeof value === 'number' && isNaN(value); 
} 

-------------------------------First, let's see the calculation interface. Let's use language to describe it: deposit period + value date () = due date

 

The designed (date control, loss of focus event) doesn't say much, just plug in the code

//Value date focus trigger
        function startonfours(){
        	var endDate=$dp.$('endDate');
        	console.log(123)
        	//1. Get the value of the storage period text box, and perform string segmentation to determine the storage period
        	var bankSaveYear= $("#bankSaveYear").find("option:selected").text();
        	var bankSaveYearval= $("#bankSaveYear").find("option:selected").val();
        	console.log(bankSaveYearval)
        	if(bankSaveYearval !=""){
        			//Time to obtain value date
	        	var qixiri =$("#startDate").val();
	        			//Judge whether there is value
	        	if(bankSaveYear!= null && qixiri !=null){
	        		//Now we have two values---------------------------
	        		var saveYearnum = bankSaveYear.replace(/[^0-9]/ig,"");
	        		var saveYearchar = bankSaveYear.match(/[\u4e00-\u9fa5]/g).join("");
	        		//Obtain year, month and day respectively
	        		var curtDate  = new Date(qixiri);
	        		var curtYear  = parseInt(curtDate.getFullYear());
	        		var curtMonth = parseInt(curtDate.getMonth()+1);
	        		var curtTian  = parseInt(curtDate.getDate());
	        		//Latest date
	        		var now="";
	        		console.log(curtYear)
	        		console.log(curtMonth)
	        		var numTian = (curtTian) -1;
	        		//Year and month-1 of interest date
	        		if(curtMonth ===curtMonth && !isNaN(curtMonth)){
	        			if(saveYearchar =='Months' && saveYearchar!=null){
							//Month: 1. Current month + to year after December + 1
							//Current month + term (month)
							var numyue = (curtMonth)+parseInt(saveYearnum);
							console.log(numyue +"--------"+curtMonth+"---------"+saveYearnum)
							while(numyue>12){
								curtYear++;
								numyue -=12;
							}
							//Accurately calculate the date
							now = curtYear+"-"+numyue+"-"+numTian;
							console.log(now);
							$("#endDate").val(now);
						}
						//Judgement year
						if(saveYearchar =='year' && saveYearchar!=null){
							//Current year + term (year)
							var numYear = (curtYear)+parseInt(saveYearnum);
							console.log(numyue +"--------"+curtMonth+"---------"+saveYearnum)
							//Accurately calculate the date
							
							now = numYear+"-"+curtMonth+"-"+numTian;
							console.log(now);
							$("#endDate").val(now);
						}
						
						//Judgement day
						if(saveYearchar =='day' && saveYearchar!=null){
							//Days: 1. Current days + to 1,3,5,7,8,10,12: 31 days per month, 4,6,9,11: 30 days, February: 29 days,
							//At the end of the month +, then month + 1, December 29 + 1, then year + 1
							//Current days + term (days) - month + 1 - year + 1
							var numDate = (curtTian)+parseInt(saveYearnum);
							console.log(numDate+"=====================================")
							if(curtMonth ==1 || curtMonth ==3 || curtMonth ==5 || curtMonth ==7 || curtMonth ==8 || curtMonth ==10 || curtMonth ==12){
								while(numDate>31){
									curtMonth++;
									numDate-=31
									while(curtMonth>12){
										curtYear++;
										curtMonth-=12;								
									}
								}
							}
							//Accurately calculate the date numDate-1: arrival date-1 day
							var daoxiri =(numDate -1);
							now = curtYear+"-"+curtMonth+"-"+daoxiri;
							console.log(now);
							$("#endDate").val(now);
						}
	        		}
	        	}
        	}else{
        		showAlert("Please select the deposit period!","Reminder")
        	}

 

Done.