FormData()

The FormData() constructor creates a new FormData object.

Note: This feature is available in Web Workers.

Syntax

new FormData(form)

Parameters

form Optional

An HTML <form> element — when specified, the FormData object will be populated with the form's current keys/values using the name property of each element for the keys and their submitted value for the values. It will also encode file input content.

Example

The following line creates an empty FormData object:

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

You could add a key/value pair to this using FormData.append:

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

Or you can specify the optional form argument when creating the FormData object, to prepopulate it with values from the specified form:

<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>

Note: Only successful form controls are included in a FormData object, i.e. those with a name, not disabled and checked (radio buttons and checkboxes) or selected (one or more options within a select).

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

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
FormData
7
12
4
10
12
5
≤37
18
4
12
5
1.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/FormData/FormData