title: Unable to fetch POST without no-cors in header
body: <p>On making request like that:</p>
  
  <pre><code>return fetch(
              'http://localhost:8000/login',
              {   method: 'POST',
                  headers: new Headers(
                     {"Content-Type": "application/json",
                      "Accept":"application/json"}
                  ),
  
                  body: JSON.stringify(
                     {'name': 'Tom', 'password': 'Soyer'}
                  )
               }
             ).then( response =&gt; { console.log(response);})
              .catch(err =&gt; console.log(err))
  </code></pre>
  
  <p>request running with method OPTIONS instead POST.
  Only on adding mode: 'no-cors' request become POST:</p>
  
  <pre><code>return fetch(
              'http://localhost:8000/login',
              {   method: 'POST',
                  mode: 'no-cors',
                  headers: new Headers(
                     {"Content-Type": "application/json",
                      "Accept":"application/json"}
                  ),
                  body: JSON.stringify(
                     {'name': 'Tom', 'password': 'Soyer'}
                  )
               }
             ).then( response =&gt; { console.log(response);})
              .catch(err =&gt; console.log(err))
  </code></pre>
  
  <p>but response not ok than (even if network response status is 200): {type: "opaque", url: "", status: 0, ok: false, statusText: ""…}
  I suppose it because </p>
  
  <blockquote>
    <p>The only allowed values for the Content-Type header are:
    application/x-www-form-urlencoded multipart/form-data text/plain</p>
  </blockquote>
  
  <p>described here <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS" rel="noreferrer">https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS</a></p>
  
  <p>Is any way bring to live POST json data with fetch?</p>