title: jQuery append HTML form data in CSV file
body: <p>I have simple form like this</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function onSubmit( form ){
    var data = JSON.stringify( $(form).serializeArray() );
  
    console.log( data );
    return false;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;form onsubmit='return onSubmit(this)'&gt;
     &lt;fieldset&gt;
      &lt;legend&gt;Dodaj nową wymianę:&lt;/legend&gt;
    &lt;select name="size"&gt;
     &lt;option selected="selected" value="1"&gt;Wybierz rozmiar&lt;/option&gt;
     &lt;option value="1,300"&gt;1,300&lt;/option&gt;
     &lt;option value="1,372"&gt;1,372&lt;/option&gt;
     &lt;option value="1,500"&gt;1,500&lt;/option&gt;
     &lt;option value="1,524"&gt;1,524&lt;/option&gt;
     &lt;option value="1,600"&gt;1,600&lt;/option&gt;
     &lt;option value="1,700"&gt;1,700&lt;/option&gt;
     &lt;option value="1,750"&gt;1,750&lt;/option&gt;
     &lt;option value="1,800"&gt;1,800&lt;/option&gt;
     &lt;option value="1,8288"&gt;1,8288&lt;/option&gt;
     &lt;option value="1,8288 zcięte"&gt;1,8288 zcięte&lt;/option&gt;
     &lt;option value="1,829"&gt;1,829&lt;/option&gt;
     &lt;option value="2,000"&gt;2,000&lt;/option&gt;
     &lt;option value="2,032"&gt;2,032&lt;/option&gt;
     &lt;option value="2,070"&gt;2,070&lt;/option&gt;
     &lt;option value="2,100"&gt;2,100&lt;/option&gt;
     &lt;option value="2,200"&gt;2,200&lt;/option&gt;
     &lt;option value="2,240"&gt;2,240&lt;/option&gt;
     &lt;option value="2,250"&gt;2,250&lt;/option&gt;
     &lt;option value="2,350"&gt;2,350&lt;/option&gt;
     &lt;option value="2,500"&gt;2,500&lt;/option&gt;
    &lt;/select&gt;
    &lt;input type="number" name="quantity" id="quantity" placeholder="podaj ilość" /&gt;
    &lt;input type="text" name="date" id="date" placeholder="dd-mm-rrrr" /&gt;
    &lt;label&gt;&lt;input type="radio" name="machine" value="ULM" checked="checked" /&gt;ULM&lt;/label&gt;
    &lt;label&gt;&lt;input type="radio" name="machine" value="FRENCO" /&gt;Frenco&lt;/label&gt;
    &lt;input type="text" name="who" placeholder="podaj inicjały np. DN" /&gt;
     &lt;/fieldset&gt;
     &lt;input type="submit" value="Dodaj" id="add" name="Add"/&gt;
    &lt;/form&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>And I have existing CSV file "test.csv" in the same folder as my html file with form</p>
  
  <p>how can I add data from form to this file, every submit should be new line in CSV I've tried every solution found on google and stack.</p>
  
  <p>No I can't get PHP server on this computer.</p>