FormData() to create a new FormData object.

Reference:

https://developer.mozilla.org/en-US/docs/Web/API/FormData/FormData

 

Syntax:

new FormData(form) 

Example 1:

var formData = new FormData(); // Currently empty 

formData.append('username', 'Chris');  

Example 2:

 <form id="myForm" name="myForm">
  <div>
    <label for="username">Enter name:</label>
    <input type="text" id="username" name="username">
  </div>
  <div>
    <label for="useracc">Enter account number:</label>
    <input type="text" id="useracc" name="useracc">
  </div>
  <div>
    <label for="userfile">Upload file:</label>
    <input type="file" id="userfile" name="userfile">
  </div>
  <input type="submit" value="Submit!">
</form>

 let myForm = document.getElementById('myForm');
let formData = new FormData(myForm);