JSFiddle - React, Tailwind, and code Playground

HTML

<div class="entry">
<h1>Podsadové stany &#8211; plachty</h1>
   	<div id="ninja_forms_form_7_cont" class="ninja-forms-cont">
		<div id="ninja_forms_form_7_wrap" class="ninja-forms-form-wrap">
	<div id="ninja_forms_form_7_response_msg" style="" class="ninja-forms-response-msg "></div>	<form id="ninja_forms_form_7" enctype="multipart/form-data" method="post" name="" action="" class="ninja-forms-form">

		<input type="hidden" name="_ninja_forms_display_submit" value="1">
	<input type="hidden" name="_form_id"  id="_form_id" value="7">
		<div id="ninja_forms_form_7_all_fields_wrap" class="ninja-forms-all-fields-wrap">
		<h2 class="ninja-forms-field " id="ninja_forms_field_163_div_wrap" style="" rel="163"><p>Výběr stanového plátna</p>
</h2>
							<div class="field-wrap list-dropdown-wrap label-above"  id="ninja_forms_field_165_div_wrap" data-visible="1">
							<input type="hidden" id="ninja_forms_field_165_type" value="list">
		<input type="hidden" id="ninja_forms_field_165_list_type" value="dropdown">
				<label for="ninja_forms_field_165" id="ninja_forms_field_165_label" class="">Rozměry stran podsady 				</label>
					<select name="ninja_forms_field_165" id="ninja_forms_field_165" class="ninja-forms-field " rel="165">
									<option value="200x200cm" selected style="" >200x200cm</option>
									<option value="205x205cm"  style="" >205x205cm</option>
							</select>
				<div id="ninja_forms_field_165_error" style="display:none;" class="ninja-forms-field-error">
		</div>
							</div>
												<div class="field-wrap list-dropdown-wrap label-above"  id="ninja_forms_field_166_div_wrap" data-visible="1">
							<input type="hidden" id="ninja_forms_field_166_type" value="list">
		<input type="hidden" id="ninja_forms_field_166_list_type" value="dropdown">
				<label for="ninja_forms_field_166" id="ninja_forms_field_166_label" class="">Výška stanu <span class='ninja-forms-req-symbol'>*</span>				</label>
					<select name="ninja_forms_field_166"...

JavaScript

function spocitejHodnotu() {
    
    var rozmer = jQuery('#ninja_forms_field_165 option:selected').text();
    var vyska = jQuery('#ninja_forms_field_166 option:selected').text();
    var barva = jQuery('#ninja_forms_field_167 option:selected').text();
    
    var is200 = /200x200cm/i.test(rozmer);
    var is205 = /205x205cm/i.test(rozmer);
    var is140 = /140/i.test(vyska);
    var is150 = /150/i.test(vyska);
    var is160 = /160/i.test(vyska);
    var isRezna = /režná/i.test(barva);
    var isSeda= /šedá/i.test(barva);
    var isSahara=/sahara/i.test(barva);
    var isKhaki=/khaki/i.test(barva);
    var is440=/režná 440g na m2/i.test(barva);  
    var hodnota = 0;
    
    if (is200) {
      if (is140) {
        if (isRezna) {
            hodnota=2380;
         } else if(isSeda){
            hodnota=2520;
        } else if(isSahara){
            hodnota=2520;
        } else if(isKhaki){
            hodnota=2600;
        } else if(is440){
            hodnota=3000;
        }
      }
      if (is150) {
        if (isRezna) {
            hodnota=2480;
         } else if(isSeda){
            hodnota=2620;
        } else if(isSahara){
            hodnota=2620;
        } else if(isKhaki){
            hodnota=2700;
        } else if(is440){
            hodnota=3100;
        }
      }
      if (is160) {
        if (isRezna) {
            hodnota=2780;
         } else if(isSeda){
            hodnota=2920;
        } else if(isSahara){
            hodnota=2920;
        } else if(isKhaki){
            hodnota=3000;
        } else if(is440){
            hodnota=3500;
        }
      }
    }
    if (is205) {
      if (is140) {
        if (isRezna) {
            hodnota=2480;
         } else if(isSeda){
            hodnota=2620;
        } else if(isSahara){
            hodnota=2620;
        } else if(isKhaki){
            hodnota=2700;
        } else if(is440){
            hodnota=3100;
        }
      }
      if (is150) {
        if (isRezna) {
            hodnota=2580;
  ...