JSFiddle - React, Tailwind, and code Playground

HTML

<form action="https://sport4kids.biz/component/chronoforms/?chronoform=summercamps-new&amp;event=submit" name="summercamps-new" id="chronoform_summercamps-new" method="post" class="Chronoform"><div class="ccms_form_element cfdiv_header" id="id1_container_div" style=""><h2>Summer Camp</h2><div class="clear"></div></div><div class="cf_container ccms_form_element row-fluid" id="cf_container_2"><div class="cf_container ccms_form_element span9" id="cf_container_3"><div class="cf_container ccms_form_element row sc-row-holder" id="cf_container_45"><div class="cf_container ccms_form_element span3" id="cf_container_48"><div class="ccms_form_element cfdiv_select" id="sc_weeks_container_div" style=""><select size="1" id="sc-weeks" class="sc-weeks selectpicker" title="" name="sc-wpic">
<option value="">Select Week</option>
<option value="wc0728">w.c. 28th July</option>
<option value="wc0804">w.c. 04th August</option>
<option value="wc0811">w.c. 11th August</option>
<option value="wc0818">w.c. 18th August</option>
<option value="wc0825">w.c. 25th August</option>
</select>
<div class="clear"></div><div id="error-message-sc-wpic"></div></div><div class="clear"></div></div><div class="cf_container ccms_form_element span3" id="cf_container_52"><div class="ccms_form_element cfdiv_checkboxgroup" id="sc_dpic1_container_div" style=""><select multiple="multiple" size="1" class="sc-days selectpicker" title="" name="sc-dpic[]">
<option value="">Select Day</option>
<option value="" selected="selected"></option>
</select>
<div class="clear"></div><div id="error-message-sc-dpic"></div></div><div class="clear"></div></div><div class="cf_container ccms_form_element span3" id="cf_container_56"><div class="ccms_form_element cfdiv_checkboxgroup" id="dpedo1_container_div" style=""><select multiple="multiple" size="1" class="sc-edo selectpicker" title="" name="dpEDO[]">
<option value="">Select Early Drop off Days</option>
<option value="" selected="selected"></option>
</select>
<div...

JavaScript

(function ($) {
    $(document).ready(function () {
$('#sc-weeks').change(function() {
    var mn = new day('Monday', $(this).val() + "_0");
    $('.sc-days').empty();
    dayArray = [mn];
    alert(dayArray[0].value);
});
});
})(jQuery);
function day(key, value) {
    this.key = key;
    this.value = value;
}
function addToCart(item, previousItem) {
    var cart = $('#cartlist');
    $('.emptyText').remove();
    cart.prepend(item);
}

function removeFromCart(itemID) {
    var itemToRemove = $('.' + itemID);
    itemToRemove.remove();
    isCartEmpty();
}

function isCartEmpty() {
    var cart = $('#cartlist');
    var cartT = $('#cartlist li');
    if (cartT.length === 0) {
        cart.prepend('<p class="emptyText">You haven\'t selected any classes. Pick a date from the left</p>');
    }
}

function pickAll() {
    var dates = $('form input:checkbox');
    dates.each(function () {
        this.click();
    });
}

function emptyCart() {
    var cart = $('#cartlist');
    cart.empty();
    isCartEmpty();
}