Javascript tips for adding or subtracting dates by month

JavaScript code example for date addition and subtraction. Because JavaScript does not have the AddDays method similar to C #, you need to write a function to implement date addition and subtraction. I will share it with you here. if you have any friends, you can refer to the projects you need and write one for yourself. Javascript date plus or minus by month

  
   Script function dateToDate (date) {var sDate = new Date (); if (typeof date = 'object' & typeof new Date (). getMonth = "function") {sDate = date;} else if (typeof date = "string") {var arr = date. split ('-') if (arr. length = 3) {sDate = new Date (arr [0] + '-' + arr [1] + '-' + arr [2]);} return sDate;} function addMonth (date, num) {num = parseInt (num); var sDate = dateToDate (date); var s Year = sDate. getFullYear (); var sMonth = sDate. getMonth () + 1; var sDay = sDate. getDate (); var eYear = sYear; var eMonth = sMonth + num; var eDay = sDay; while (eMonth> 12) {eYear ++; eMonth-= 12 ;} var eDate = new Date (eYear, eMonth-1, eDay); while (eDate. getMonth ()! = EMonth-1) {eDay --; eDate = new Date (eYear, eMonth-1, eDay);} return eDate;} function calcDate () {var d = document. getElementById ('date '). value; var n = document. getElementById ('num '). value; var eDate = addMonth (d, n); document. getElementById ('result '). innerHTML = eDate. getFullYear () + '-' + (eDate. getMonth () + 1) + '-' + eDate. getDate ();} script        

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