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
XMLHttpRequest Standard (XMLHttpRequest)
# interface-formdata

Browser compatibility

BCD tables only load in the browser

See also