How to validate form using jQuery

Question

I know there are a number of answers available for this question but I want to validate the whole form with dynamic input fields coming from a database like Google Forms.

Html

<div class="rs_card"><span style="font-size: 1em;">How to create website like programmer?</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

<div class="rs_card"><span style="font-size: 1em;">How to create art like painter?</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

<div class="rs_card"><span style="font-size: 1em;">How to create transition effect like materialize css</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

JS

$(document).ready(function(){    
    $('input.required').each(function(){
        $(this).on('input', function(){
            if($(this).val() == ''){
                $(this).parents('div.rs_card').addClass('invalid_card');
            } else{
                $(this).parents('div.rs_card').removeClass('invalid_card');
            }
        });
    });
});

I also try keyup instead of input but not working. This line of code below is working fine (tested with other conditions).

$(this).parents('div.rs_card').addClass('invalid_card');

This code isn't working, can anyone tell me what is wrong with this code?

Answer 1

Does 'change' work for you?.
Like this:
Of course remove the console.log() statements and change the if condition before you use this anywhere.
It's just for demonstration.

$(document).ready(function(){    
    $('input.required').each(function(){
        $(this).on('change', function(){
            if($(this).val() == '123'){
                    console.log("if");
                $(this).parents('div.rs_card').addClass('invalid_card');
            } else{
                console.log("else");
                $(this).parents('div.rs_card').removeClass('invalid_card');
            }
        });
    });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div class="rs_card"><span style="font-size: 1em;">How to create website like programmer?</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

<div class="rs_card"><span style="font-size: 1em;">How to create art like painter?</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

<div class="rs_card"><span style="font-size: 1em;">How to create transition effect like materialize css</span><div class="col-3" style="margin-top: 5%"><input type="text" placeholder="Placeholder Text" class="input_field required"><span class="focus-border"></span></div></div>

This also works with "keyup" but then of course fires everytime the user releases a keypress: https://jsfiddle.net/Chazlol/1co0y4ju/16/