The FormData interface provides a way to construct a set of key/value pairs representing form fields and their values, which can be sent using the navigator.sendBeacon() methods. 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 <form> would do if it were using simple GET submission.

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

Constructor

FormData(): Creates a new FormData object.

Instance 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 that iterates through all key/value pairs contained in the FormData.
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 whether a FormData object contains a certain key.
FormData.keys(): Returns an iterator iterates through all keys of the key/value pairs contained in the FormData.
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 that iterates through all values contained in the FormData.

Specifications

Specification
XMLHttpRequest # interface-formdata

Browser compatibility

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