FormData

The FormData interface provides a way to easily construct a set of key/value pairs representing form fields and their values, which can then be easily sent using the XMLHttpRequest.send() method. It uses the same format a form would use if the encoding type were set to "multipart/form-data".

You can also pass it directly to the URLSearchParams constructor if you want to generate query parameters in the way a <form> would do if it were using simple GET submission.

An object implementing FormData can directly be used in a for...of structure, instead of entries(): for (var p of myFormData) is equivalent to for (var p of myFormData.entries()).

Note: This feature is available in Web Workers.

Constructor

FormData()
Creates a new FormData object.

Methods

FormData.append()
Appends a new value onto an existing key inside a FormData object, or adds the key if it does not already exist.
FormData.delete()
Deletes a key/value pair from a FormData object.
FormData.entries()
Returns an iterator allowing to go through all key/value pairs contained in this object.
FormData.get()
Returns the first value associated with a given key from within a FormData object.
FormData.getAll()
Returns an array of all the values associated with a given key from within a FormData.
FormData.has()
Returns a boolean stating whether a FormData object contains a certain key.
FormData.keys()
Returns an iterator allowing to go through all keys of the key/value pairs contained in this object.
FormData.set()
Sets a new value for an existing key inside a FormData object, or adds the key/value if it does not already exist.
FormData.values()
Returns an iterator allowing to go through all values  contained in this object.

Specifications

Specification Status Comment
XMLHttpRequest
The definition of 'FormData' in that specification.
Living Standard FormData defined in XHR spec

Browser compatibility

BCD tables only load in the browser

See also