JSFiddle - React, Tailwind, and code Playground

HTML

<br/><br/>
Date : <input type="text" id="txtDate" /> (yyyy/mm/dd)
<br/><br/><br/>
<input type="button" value="ValidateDate" id="btnSubmit"/>

CSS

body{
    font-family:Tahoma;
    font-size : 8pt;
    padding-left:10px;
}
input[type="text"]
{
   font-family:Tahoma;
   font-size : 8pt;
   width:150px;
}

JavaScript

$(function() {
    $('#btnSubmit').bind('click', function(){
        var txtVal =  $('#txtDate').val();
        if(isDate(txtVal))
            alert('Valid Date');
        else
            alert('Invalid Date');
    });
    
function isDate(txtDate)
{
    var currVal = txtDate;
    if(currVal == '')
        return false;
    
    var rxDatePattern = /^(\d{4})(\/|-)(\d{1,2})(\/|-)(\d{1,2})$/; //Declare Regex
    var dtArray = currVal.match(rxDatePattern); // is format OK?
    
    if (dtArray == null) 
        return false;
    
    //Checks for mm/dd/yyyy format.
    dtMonth = dtArray[3];
    dtDay= dtArray[5];
    dtYear = dtArray[1];        
    
    if (dtMonth < 1 || dtMonth > 12) 
        return false;
    else if (dtDay < 1 || dtDay> 31) 
        return false;
    else if ((dtMonth==4 || dtMonth==6 || dtMonth==9 || dtMonth==11) && dtDay ==31) 
        return false;
    else if (dtMonth == 2) 
    {
        var isleap = (dtYear % 4 == 0 && (dtYear % 100 != 0 || dtYear % 400 == 0));
        if (dtDay> 29 || (dtDay ==29 && !isleap)) 
                return false;
    }
    return true;
}

});