date validation in javascript – How to check a date is valid or not using JavaScript?

date validation in javascript – Validate Date Using Regular Expressions, the moment.js Library and Date.parse() Method in JavaScript Example with demo.

How to check a date is valid or not using 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 Format	Regex
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

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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.

Validate Date Using Regular Expressions in JavaScript

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

Date of Birth (Age) Validation in JavaScript

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