Js gets a small example of the number of weeks specified by the date and the day of the week

When JS gets a date, it encounters the following requirement to get a week's date based on a week of a year. If the starting date is Thursday, the following week's Friday is one week.

The code is as follows:

function getNowFormatDate(theDate) 
{ 
var day = theDate; 
var Year = 0; 
var Month = 0; 
var Day = 0; 
var CurrentDate = ""; 
//Initialization time
Year= day.getFullYear();//Internet explorer or firefox
Month= day.getMonth()+1; 
Day = day.getDate(); 
CurrentDate += Year + "-"; 
if (Month >= 10 ) 
{ 
CurrentDate += Month + "-"; 
} 
else 
{ 
CurrentDate += "0" + Month + "-"; 
} 
if (Day >= 10 ) 
{ 
CurrentDate += Day ; 
} 
else 
{ 
CurrentDate += "0" + Day ; 
} 
return CurrentDate; 
} 

function isInOneYear(_year,_week){ 
if(_year == null || _year == '' || _week == null || _week == ''){ 
return true; 
} 
var theYear = getXDate(_year,_week,4).getFullYear(); 
if(theYear != _year){ 
return false; 
} 
return true; 
} 

//Gets the date range display
function getDateRange(_year,_week){ 
var beginDate; 
var endDate; 
if(_year == null || _year == '' || _week == null || _week == ''){ 
return ""; 
} 
beginDate = getXDate(_year,_week,4); 
endDate = getXDate(_year,(_week - 0 + 1),5); 
return getNowFormatDate(beginDate) + "  to  "+ getNowFormatDate(endDate); 
} 

//This method takes the date of the weekDay of a year
function getXDate(year,weeks,weekDay){ 
//Construct a date object with the specified year and set the date to January 1 of that year
//Since the month in the computer starts at 0, there is the following construction
var date = new Date(year,"0","1"); 

//Gets the long integer time of this date object, date
var time = date.getTime(); 

//I'm going to offset this long shaping time by the time of week N
//Because the first week is the current week, there is :weeks-1, and so on
//7*24*3600000 is the number of milliseconds in a week.
time+=(weeks-1)*7*24*3600000; 

//Reset the date object date to time
date.setTime(time); 
return getNextDate(date,weekDay); 
} 
//This method gets the weekDay date of the week in which the nowDate is
function getNextDate(nowDate,weekDay){ 
//0 is Sunday,1 is Monday,...
weekDay%=7; 
var day = nowDate.getDay(); 
var time = nowDate.getTime(); 
var sub = weekDay-day; 
if(sub <= 0){ 
sub += 7; 
} 
time+=sub*24*3600000; 
nowDate.setTime(time); 
return nowDate; 
}

For the first week of 2016, start from Thursday. The date range for the first week is 2016-01-07 to 2016-01-15

In providing a section of the call reference code:

//Date processing
function dateRange(){ 
var _year = $("#_year").val(); 
var _week = $("#_week").val(); 
if(isInOneYear(_year,_week)){ 
var showDate = getDateRange(_year,_week); 
$("#_dateRange_import").html(showDate); 
} else{ 
alert(_year+" In no "+_week+" Zhou, please choose again "); 
$("#_week").val(""); 
} 
}