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Roosevelt Hettinger

Roosevelt Hettinger

1 year ago

How to Validate Dates in JavaScript

A JavaScript function is used to check a valid date format against a regular expression.

Date Validation as Text Format in JavaScript

Validation Function

function validatedate(dateString){
let dateformat = /^(0?[1-9]|1[0-2])[\/](0?[1-9]|[1-2][0-9]|3[01])[\/]\d{4}$/;

if(dateString.match(dateformat)){
let operator = dateString.split('/');

let secDateInfo = [];
if (operator.length>1){
secDateInfo = dateString.split('/');
}
let curr_mon= parseInt(secDateInfo[0]);
let day = parseInt(secDateInfo[1]);
let year = parseInt(secDateInfo[2]);

let totalNoOfDays = [31,28,31,30,31,30,31,31,30,31,30,31];
if (curr_mon==1 || curr_mon>2){
if (day>totalNoOfDays[curr_mon-1]){
return false;
}
}else if (curr_mon==2){
let applpYear = false;
if ( (!(year % 4) && year % 100) || !(year % 400)) {
applpYear = true;
}
if ((applpYear == false) && (day>=29)){
return false;
}else
if ((applpYear==true) && (day>29)){
console.log('Sorry, Invalid date format!');
return false;
}
}
}else{
console.log("Invalid date format!");
return false;
}
return true;
}

Example

var a = validatedate("06/16/2021");
console.log(a);

Sample Regex for Date Format

Date FormatRegex
MM/DD/YYYY 
M/DD/YYYY/^(0?[1-9]|1[0-2])[\/](0?[1-9]|[1-2][0-9]|3[01])
MM/D/YYYY[\/]\d{4}$/
M/D/YYYY 
DD/MM/YYYY 
D/MM/YYYY /^(0?[1-9]|[1-2][0-9]|3[01])[\/](0?[1-9]|1[0-2])
DD/M/YYYY [\/]\d{4}$/
D/M/YYYY 

Validate Date With With Date.parse() Method in JavaScript

Date Validation as Text Format in JavaScript – The Data.parse() is a function that is already available in core JavaScript.

<!DOCTYPE html>
<html lang="en">
<head>
<title>Validate Date With With Date.parse() Method in JavaScript - www.pakainfo.com</title>
</head>
<body>
<h2 id="pakainfo_new_dsiplay_status"></h2>

<script>
let isValidDate = Date.parse('03/17/21');

if (isNaN(isValidDate)) {
document.getElementById('pakainfo_new_dsiplay_status').innerHTML = "It is not a valid date format.";
}
else{
document.getElementById('pakainfo_new_dsiplay_status').innerHTML = "It is a valid date format.";
}

</script>
</body>
</html>

Validate Date Using Regular Expressions in JavaScript

<!DOCTYPE html>
<html lang="en">
<head>
<title>Document</title>
</head>
<body>
<h2 id="pakainfo_new_dsiplay_status"></h2>
<script>

var date_regex = /^(0[1-9]|1[0-2])\/(0[1-9]|1\d|2\d|3[01])\/(0[1-9]|1[1-9]|2[1-9])$/;
var testDate = "03/17/21"
if (date_regex.test(testDate)) {
document.getElementById("pakainfo_new_dsiplay_status").innerHTML = "Date follows dd/mm/yy format";
}
else{
document.getElementById("pakainfo_new_dsiplay_status").innerHTML = "Invalid date format";
}

</script>
</body>
</html>

Validate Date With the moment.js Library in JavaScript

First of all open your cmd terminal and run this bellow commands.

npm install -g moment --save

Example

import * as moment from 'moment';

let result = moment("05/22/21", 'MM/DD/YY',true).isValid();
console.log(result)

Date of Birth (Age) Validation in JavaScript

HTML Markup

<input type="text" id="txtDate" onblur = "CheckBirthDate()" />
<span class="error" id="displayErr"></span>
<br />
<br />
<input type="button" id="btnValidate" value="Validate" onclick="return CheckBirthDate()" />

Date of Birth (Age) Validation in JavaScript

<script type="text/javascript">
function CheckBirthDate() {
var displayErr = document.getElementById("displayErr");

var dateString = document.getElementById("txtDate").value;
var regex = /(((0|1)[0-9]|2[0-9]|3[0-1])\/(0[1-9]|1[0-2])\/((19|20)\d\d))$/;

if (regex.test(dateString)) {
var infoChecks = dateString.split("/");
var bDate = new Date(infoChecks[1] + "/" + infoChecks[0] + "/" + infoChecks[2]);
var activeDt = new Date();
displayErr.innerHTML = "Hello Dear , Eligibility 18 years ONLY."
if (activeDt.getFullYear() - bDate.getFullYear() < 18) {
return false;
}

if (activeDt.getFullYear() - bDate.getFullYear() == 18) {

if (activeDt.getMonth() < bDate.getMonth()) {
return false;
}
if (activeDt.getMonth() == bDate.getMonth()) {
if (activeDt.getDate() < bDate.getDate()) {
return false;
}
}
}
displayErr.innerHTML = "";
return true;
} else {
displayError.innerHTML = "Enter date in dd/MM/yyyy format ONLY."
return false;
}
}
</script>

I hope you get an idea about date validation in javascript.

#javascript 

How to Validate Dates in JavaScript
1.00 GEEK