title: what is Cors-Policy why it is not allowing me to use content- type in post request of Fecth API in javascript?
body: <p>it is showing like this when i am running the post request in console</p>
  <pre><code>Access to fetch at 'http://dummy.restapiexample.com/api/v1/create' from origin 'http://127.0.0.1:5501' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.
  tut42.js:57 POST http://dummy.restapiexample.com/api/v1/create net::ERR_FAILED
  postData @ tut42.js:57
  (anonymous) @ tut42.js:61
  tut42.js:57   Uncaught (in promise) TypeError: Failed to fetch
      at postData (tut42.js:57)
      at tut42.js:61
  postData @ tut42.js:57
  (anonymous) @ tut42.js:61
  Promise.then (async)
  postData @ tut42.js:58
  (anonymous) @ tut42.js:61
  </code></pre>