title: submit and display checkboxes values without submit button
body: <p>I've a sort of e-commerce and in the checkout page I display the price.</p>
  
  <p>In the same page, I've some "services" to add to the final price and this are showed with checkboxes.</p>
  
  <p>Now I want that when I click on a checkbox the price will be updated with a sum. </p>
  
  <p>Something like this: 'price' + 'service_1' + 'service_2' = total price</p>
  
  <p>and I want that the services will be displayed in the other div dynamically</p>
  
  <p>My problem is that i don't know how to update the price and display it in a div without a submit button.</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-html lang-html prettyprint-override"><code>&lt;form id="services" name="services-form" data-name="services Form"&gt;
    &lt;div class="checkbox-field w-checkbox"&gt;&lt;input type="checkbox" id="service_1" name="checkbox" data-name="Checkbox" class="checkbox 1 w-checkbox-input"&gt;&lt;label for="checkbox" class="simple-text white w-form-label"&gt;design pack&lt;/label&gt;22500 €&lt;/div&gt;
    &lt;div class="checkbox-field ew w-checkbox"&gt;&lt;input type="checkbox" id="service_2" name="checkbox-2" data-name="service_2" class="checkbox 2 w-checkbox-input"&gt;&lt;label for="checkbox-2" class="simple-text white w-form-label"&gt;security&lt;/label&gt;2000 €&lt;/div&gt;
    &lt;div class="checkbox-field 2 w-checkbox"&gt;&lt;input type="checkbox" id="service_3" name="checkbox-2" data-name="service_3" class="checkbox 3 w-checkbox-input"&gt;&lt;label for="checkbox-3" class="simple-text white w-form-label"&gt;wellness pack&lt;/label&gt;5000 €&lt;/div&gt;
    &lt;div class="checkbox-field 4 w-checkbox"&gt;&lt;input type="checkbox" id="service_4" name="checkbox-2" data-name="service_4" class="checkbox 4 w-checkbox-input"&gt;&lt;label for="checkbox-3" class="simple-text white w-form-label"&gt;box auto&lt;/label&gt;1000 €&lt;/div&gt;
  &lt;/form&gt;
  
  &lt;div class="paragraph" id="price"&gt;
    &lt;?php echo $price;?&gt; €&lt;/div&gt;
  &lt;div id="display_services" class="simple-text maiusc prova"&gt;services:&lt;br&gt;design pack&lt;br&gt;dynamically adding the services...&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>