Why http request send twice from client to server ( OPTION and POST )
<p>When I click the submit button, http request send twice from client to server. 
first one is OPTIONS and other one is POST method. </p>

<p><strong>login form</strong>
<a href="https://i.stack.imgur.com/TVwC7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TVwC7.png" alt="enter image description here"></a></p>

<p><strong>HTTP Requests</strong> 
<a href="https://i.stack.imgur.com/UGmTM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UGmTM.png" alt="enter image description here"></a></p>