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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".

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 compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	7	Yes	4 4 Prior to Firefox 7, specifying a `Blob` as the data to append to the object, the filename reported in the `Content-Disposition` HTTP header was an empty string, resulting in errors on some servers. Starting with Firefox 7, the filename `blob` is sent.	10	12	5
`FormData()` constructor	7	Yes	4	10	12	5
`append`	7	Yes	4 4 Prior to Firefox 7, specifying a `Blob` as the data to append to the object, the filename reported in the `Content-Disposition` HTTP header was an empty string, resulting in errors on some servers. Starting with Firefox 7, the filename `blob` is sent.	10 10 With the "Include local directory pass when uploading files to a server" option enabled, IE will change the filename inside the `Blob` on the fly. To have direct control of the sent filename, the developer should send the filename as the third parameter value, i.e. `formData.append(name, value, filename)`.	12	5
`delete`	50	No	39	No	Yes	11
`get`	50	No	39	No	Yes	11
`getAll`	50	No	39	No	Yes	11
`has`	50	No	39	No	Yes	11
`set`	50	No	39	No	No	11
`entries`	50	No	44	No	Yes	11
`keys`	50	No	44	?	Yes	11
`values`	50	No	44	?	?	11
Support of `for...of`	50	No	44	?	?	11
Available in workers	Yes	Yes	39	No	Yes	Yes

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	Yes Yes XHR in Android 4.0 sends empty content for `FormData` with `blob`.	Yes	Yes	4	12	?	?
`FormData()` constructor	Yes	Yes	Yes	Yes	12	?	?
`append`	3 3 XHR in Android 4.0 sends empty content for `FormData` with `blob`.	?	Yes	4 4 Prior to Firefox 7, specifying a `Blob` as the data to append to the object, the filename reported in the `Content-Disposition` HTTP header was an empty string, resulting in errors on some servers. Starting with Firefox 7, the filename `blob` is sent.	12	?	?
`delete`	?	50	No	Yes	Yes	No	?
`get`	?	50	No	Yes	Yes	No	?
`getAll`	?	50	No	Yes	Yes	No	?
`has`	?	50	No	Yes	Yes	No	?
`set`	?	50	No	Yes	No	No	?
`entries`	?	50	No	44	Yes	?	?
`keys`	?	50	No	44	?	?	?
`values`	?	50	No	44	?	?	?
Support of `for...of`	?	50	No	44	?	?	?
Available in workers	Yes	Yes	Yes	Yes	Yes	No	?

FormData

Constructor

Methods

Specifications

Browser compatibilityUpdate compatibility data on GitHub

See also