JSFiddle - React, Tailwind, and code Playground

HTML

<tr>
        <td>
            <span id="MainContent_lblBusinessCenter" style="font-family:Open Sans;">BC:</span></td>
        <td>
            <select name="ctl00$MainContent$ddlBusinessCenter" onchange="javascript:setTimeout(&#39;__doPostBack(\&#39;ctl00$MainContent$ddlBusinessCenter\&#39;,\&#39;\&#39;)&#39;, 0)" id="MainContent_ddlBusinessCenter" margin-Left="100px" style="font-family:Merriweather;height:30px;width:120px;">
	<option value=""></option>
	<option selected="selected" value="1">RH</option>
	
	<option value="8">CR</option>
	<option value="9">TU</option>
	<option value="10">VR</option>
	<option value="11">VC</option>

</select><br />
        </td>
        
    </tr>
    
    <div id="MainContent_UpdatePanel2">
	
    <tr>
        <td>
            <span id="MainContent_ProductHierarchy1" style="font-family:Open Sans;">Product Level 1:</span></td>
        <td>
            <select name="ctl00$MainContent$ddlProductHierarchyLvL1" onchange="javascript:setTimeout(&#39;__doPostBack(\&#39;ctl00$MainContent$ddlProductHierarchyLvL1\&#39;,\&#39;\&#39;)&#39;, 0)" id="MainContent_ddlProductHierarchyLvL1" margin-Left="100px" style="font-family:Merriweather;height:30px;width:120px;">
		<option selected="selected" value=""></option>

		<option value="T">Textile flooring</option>
		<option value="V">Vinyl flooring</option>
		<option value="W">Wood flooring</option>

	</select><br />
        </td>
        
    </tr>
 
    <tr>
        <td>
            <span id="MainContent_ProductHierarchy2" style="font-family:Open Sans;">Product Leve2:</span></td>
        <td>
            <select name="ctl00$MainContent$ddlProductHierarchyLvL2" onchange="javascript:setTimeout(&#39;__doPostBack(\&#39;ctl00$MainContent$ddlProductHierarchyLvL2\&#39;,\&#39;\&#39;)&#39;, 0)" id="MainContent_ddlProductHierarchyLvL2" margin-Left="100px" style="font-family:Merriweather;height:30px;width:120px;">
<option selected="selected" value=""></option>
		<option value="A">Accessories</option>

		<option...

CSS

.IDKarakteristike
{
    display: none !important;
}

JavaScript

$(function () {
            
            $(".IDMandatory").each(function (i, el) {
                if ($(el).text().toUpperCase() === "TRUE") {
                    $(el).closest("tr").find("input,select").prop("required", true);
                }
            });

           
            $("#myButton").on("click", function () {
               
                var ok = true;              
               
                $("[required]").each(function () {
                    $(this).css("border", ""); // reset
                    if (!$(this).val()) {
                        ok = false;
                        $(this).css("border", "2px solid red");
                        var message = "";
                        if ($("#MainContent_ddlProductHierarchyLvL1").val() == 0) {
                            message += "Plase fill in the GPR PIM Product Hierarchy Level 1 field!";
                        }
                        if ($("#MainContent_ddlProductHierarchyLvL2").val() == 0) {
                            message += "Plase fill in the GPR PIM Product Hierarchy Level 2 field!";
                        }
                        if ($("#MainContent_ddlProductHierarchyLvL3").val() == 0) {
                            message += "Plase fill in the GPR PIM Product Hierarchy Level 3 field!";
                        }
                        if (message != "") {
                            alert(message);
                        }
                    }
                
                });

           
                if (ok) {
                     var ddl = $('#MainContent_ddlBusinessCenter').val()

                    var myCollection = [];

                    $('#MainContent_gvKarakteristike tbody').find('tr:gt(0)').each(function (i, e) {
                        var row = $(e);
                        myCollection.push({
                            label: valuefromType(row.find(row.find('td:eq(1)').children())),
                            opis:...