javascript - Populate dropdown list with current day, month and year - Stack Overflow

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I am probably asking an easy question for you, but I am still a newbie, so please someone help me. I have this html and jQuery code:

$(document).ready(function() {
    var d = new Date();
    var month = d.getMonth() + 1;
    var year = d.getFullYear();

    $("#month").val(month); 
    $("#year").val(year);    
    
});

<script src=".1.1/jquery.min.js"></script>
<select id="month">
    <option value="1">January</option>
    <option value="2">February</option>
    <option value="3">March</option>
    <option value="4">April</option>
    <option value="5">May</option>
    <option value="6">June</option>
    <option value="7">July</option>
    <option value="8">August</option>
    <option value="9">September</option>
    <option value="10">October</option>
    <option value="11">November</option>
    <option value="12">December</option>
</select>
<select id="year">
    <option value="2015">2015</option>
    <option value="2016">2016</option>
    <option value="2017">2017</option>
    <option value="2018">2018</option>
</select>

I am probably asking an easy question for you, but I am still a newbie, so please someone help me. I have this html and jQuery code:

$(document).ready(function() {
    var d = new Date();
    var month = d.getMonth() + 1;
    var year = d.getFullYear();

    $("#month").val(month); 
    $("#year").val(year);    
    
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="month">
    <option value="1">January</option>
    <option value="2">February</option>
    <option value="3">March</option>
    <option value="4">April</option>
    <option value="5">May</option>
    <option value="6">June</option>
    <option value="7">July</option>
    <option value="8">August</option>
    <option value="9">September</option>
    <option value="10">October</option>
    <option value="11">November</option>
    <option value="12">December</option>
</select>
<select id="year">
    <option value="2015">2015</option>
    <option value="2016">2016</option>
    <option value="2017">2017</option>
    <option value="2018">2018</option>
</select>

So the question is: How can I populate one more dropdown showing current day, but also showing all the days from the month, based on if they are 30, 31, 28 or even leap year (29 days in Fevruary)? Any help will be appreciated. P.S. And also can this be done more dynamically ?

• javascript
• jquery
• html

Share Improve this question Follow edited Aug 2, 2018 at 18:26 NewJavaEnthusiast asked Aug 2, 2018 at 17:43 NewJavaEnthusiastNewJavaEnthusiast 10322 gold badges44 silver badges1414 bronze badges 4

• d.getDate() ? – Calvin Nunes Commented Aug 2, 2018 at 18:03
• @CalvinNunes well it will work, but what about the months with 30 days or February (in or out of a leap year)? – NewJavaEnthusiast Commented Aug 2, 2018 at 18:24
• I added an answer below, please check it – Calvin Nunes Commented Aug 2, 2018 at 18:34
• pub.dev/packages/flutter_rounded_date_picker use this library for dropdown view in flutter. – s.j Commented Sep 18, 2020 at 9:34

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4 Answers 4

Sorted by: Reset to default 18

Well, instead of writing a lot of options tag, why not let a loop do it for you... check my code below please, I'll give a brief explanation below that.

(This code uses jQuery, but it is easily achievable with vanilla JS)

$(document).ready(function() {
  const monthNames = ["January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
  ];
  let qntYears = 4;
  let selectYear = $("#year");
  let selectMonth = $("#month");
  let selectDay = $("#day");
  let currentYear = new Date().getFullYear();

  for (var y = 0; y < qntYears; y++) {
    let date = new Date(currentYear);
    let yearElem = document.createElement("option");
    yearElem.value = currentYear
    yearElem.textContent = currentYear;
    selectYear.append(yearElem);
    currentYear--;
  }

  for (var m = 0; m < 12; m++) {
    let month = monthNames[m];
    let monthElem = document.createElement("option");
    monthElem.value = m;
    monthElem.textContent = month;
    selectMonth.append(monthElem);
  }

  var d = new Date();
  var month = d.getMonth();
  var year = d.getFullYear();
  var day = d.getDate();

  selectYear.val(year);
  selectYear.on("change", AdjustDays);
  selectMonth.val(month);
  selectMonth.on("change", AdjustDays);

  AdjustDays();
  selectDay.val(day)

  function AdjustDays() {
    var year = selectYear.val();
    var month = parseInt(selectMonth.val()) + 1;
    selectDay.empty();

    //get the last day, so the number of days in that month
    var days = new Date(year, month, 0).getDate();

    //lets create the days of that month
    for (var d = 1; d <= days; d++) {
      var dayElem = document.createElement("option");
      dayElem.value = d;
      dayElem.textContent = d;
      selectDay.append(dayElem);
    }
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="year"></select>
<select id="month"></select>
<select id="day"></select>

There's a variable called qntYears, there you set how many years back from current year you want to show in the select of years...

after that, there's a loop adding all months, nothing special here.

The last part is the important one, I added a change callback to the selects of year and month. When they change, the listener recreates (using a for loop) the days based on the year and current month, it is very useful since every month has different amount of days (28, 29, 30, 31).
The function that do this is the AdjustDays().

$(document).ready(function() {
    var d = new Date();
    
    //To test 29th Feb 2016 uncomment the below line
    //d = new Date(2016, 01, 29, 10, 33, 30, 0); //
    
    var month = d.getMonth() + 1;
    var year = d.getFullYear();
    var date = d.getDate();
    
    $("#month").val(month); 
    $("#year").val(year);    

    $("#date").empty();
    if(month=="1"){
        if($(year).val()%4 == 0){
            for(i=1;i<=29;i++){
               $("#date").append($("<option></option>").attr("value", i).text(i));
            }
        }else{
            for(i=1;i<=28;i++){
                $("#date").append($("<option></option>").attr("value", i).text(i));
            }
        }
    }
    else if(month=="9" || month=="4" || month=="6" || month=="11"){
        for(i=1;i<=30;i++){
            $("#date").append($("<option></option>").attr("value", i).text(i));
        }
    }
    else{
        for(i=1;i<=31;i++){
            $("#date").append($("<option></option>").attr("value", i).text(i));
        }
    }
    $("#date").val(date);
    $('#text').html(d);
    
    //displayCalGrid(month, year); 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="date">
    
</select>
<select id="month">
    <option value="1">January</option>
    <option value="2">February</option>
    <option value="3">March</option>
    <option value="4">April</option>
    <option value="5">May</option>
    <option value="6">June</option>
    <option value="7">July</option>
    <option value="8">August</option>
    <option value="9">September</option>
    <option value="10">October</option>
    <option value="11">November</option>
    <option value="12">December</option>
</select>
<select id="year">
    <option value="2015">2015</option>
    <option value="2016">2016</option>
    <option value="2017">2017</option>
    <option value="2018">2018</option>
</select>

<br>

Today's Date is : &nbsp;<label id="text"></label>

put an event listener on the month drop down. from there you can create a list of "days" in an empty select box. I'd also use moment.js because its additional functionality to the Date object. add some validation or make each of the select boxes have a default selected value.

using plain ole javascript.

let year = document.getElementById('year');
let month = document.getElementById('month');
let days = document.getElementById('days');

month.addEventListener('change', function(event) {
    // do calculations here to find out how many days in month
    let dateString = month + "-" + year;
    let dayLength = moment(dateString, "MM-YYYY").daysInMonth();

    // wipe out all of the days
    days.innerHTML = "";

    // add back all the days.
    for(let g = 1; g < dayLength + 1; g++) {
        let option = document.createElement('option');
        option.value = g;
        days.appendChild(option);
    }
});

this is just one way, there are other ways of appending the options. like using documentFragment https://developer.mozilla.org/en-US/docs/Web/API/DocumentFragment

or you can have small templates that are already generated and placed in the dom so all you have to do is just empty out dom element containers and add dom elements back in.

Pure js.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
}
body{
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items:center;
    flex-direction: column;
}
form span{
    display: block;
    margin: 20px 0;
}
/*make form styling consistent across browsers*/
button, input, select, textarea {
    font-family: inherit;
    font-size: 100%;
  }

    </style>
</head>
<body>
        <form>
        <span>
            <label for="day">Day:</label>
            <select name="day" id="day"></select>
        </span>
        <span>
            <label for="month">Month:</label>
            <select name="month" id="month"></select>
        </span>
        <span>
            <label for="year">Year:</label>
            <select name="year" id="year">Year:</select>
        </span>
    </form>
    <script>
        //Create references to the dropdown's
const yearSelect = document.getElementById("year");
const monthSelect = document.getElementById("month");
const daySelect = document.getElementById("day");

const months = ['January', 'February', 'March', 'April', 
'May', 'June', 'July', 'August', 'September', 'October',
'November', 'December'];

//Months are always the same
(function populateMonths(){
    for(let i = 0; i < months.length; i++){
        const option = document.createElement('option');
        option.textContent = months[i];
        monthSelect.appendChild(option);
    }
    monthSelect.value = "January";
})();

let previousDay;

function populateDays(month){
    //Delete all of the children of the day dropdown
    //if they do exist
    while(daySelect.firstChild){
        daySelect.removeChild(daySelect.firstChild);
    }
    //Holds the number of days in the month
    let dayNum;
    //Get the current year
    let year = yearSelect.value;

    if(month === 'January' || month === 'March' || 
    month === 'May' || month === 'July' || month === 'August' 
    || month === 'October' || month === 'December') {
        dayNum = 31;
    } else if(month === 'April' || month === 'June' 
    || month === 'September' || month === 'November') {
        dayNum = 30;
    }else{
        //Check for a leap year
        if(new Date(year, 1, 29).getMonth() === 1){
            dayNum = 29;
        }else{
            dayNum = 28;
        }
    }
    //Insert the correct days into the day <select>
    for(let i = 1; i <= dayNum; i++){
        const option = document.createElement("option");
        option.textContent = i;
        daySelect.appendChild(option);
    }
    if(previousDay){
        daySelect.value = previousDay;
        if(daySelect.value === ""){
            daySelect.value = previousDay - 1;
        }
        if(daySelect.value === ""){
            daySelect.value = previousDay - 2;
        }
        if(daySelect.value === ""){
            daySelect.value = previousDay - 3;
        }
    }
}

function populateYears(){
    //Get the current year as a number
    let year = new Date().getFullYear();
    //Make the previous 100 years be an option
    for(let i = 0; i < 101; i++){
        const option = document.createElement("option");
        option.textContent = year - i;
        yearSelect.appendChild(option);
    }
}

populateDays(monthSelect.value);
populateYears();

yearSelect.onchange = function() {
    populateDays(monthSelect.value);
}
monthSelect.onchange = function() {
    populateDays(monthSelect.value);
}
daySelect.onchange = function() {
    previousDay = daySelect.value;
}
    </script>
</body>
</html>

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