title: Uncaught TypeError: FormData constructor: Argument 1 does not implement interface HTMLFormElement
body: <p>I created a event listener for a form  that is supposed to add a name of a owner to a dropdown I created in my HTML as I submit my form data. Well when I submit the form data I get a &quot;Uncaught TypeError: FormData constructor: Argument 1 does not implement interface HTMLFormElement.&quot; when I submit.</p>
  <p>As far as my current code....</p>
  <pre><code>      &lt;form id = &quot;owner_form&quot;&gt;
          &lt;div&gt;
            &lt;label for='name'&gt;Owner Name:&lt;/label&gt;
            &lt;input type='text' id='name' name='name' placeholder=&quot;John Doe&quot; required/&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;label for='phone_number'&gt;Phone Number:&lt;/label&gt;
            &lt;input type='text' id='phone_number' name='phone_number' placeholder=&quot;John Doe&quot; required/&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;label for='real_estate_agent'&gt;Listing Agent:&lt;/label&gt;
            &lt;input type='text' id='real_estate_agent' name='real_estate_agent' placeholder=&quot;John Doe&quot; required/&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;input type='submit' id='owner_submit' value='Submit'/&gt;
          &lt;/div&gt;
        &lt;/form&gt;
  
  
  const ownerForm = document.getElementById('owner_form')
  const ownerBtn = document.getElementById('owner_submit')
  
  ownerBtn.addEventListener('click',()=&gt;{
    ownerForm.addEventListener('submit', (event)=&gt;{
      event.preventDefault()
      let formData = new FormData(this)
      fetch(OWNERS_URL,{
        method: 'POST',
        header: {
          'Content-Type': 'application/json',
            &quot;Accept&quot;: &quot;application/json&quot;
        },
        body: JSON.stringify(formData)
      }).then(resp =&gt; resp.json()).then((owner_data) =&gt; {
        dropdown.add(owner_data.name)
      })
    })
  })
  </code></pre>
  <p>I need some help in determining why I am get the error message that I previously mentioned and how to resolve it in this case.</p>