Syntax

set(name, value)
set(name, value, filename)

Parameters

name

The name of the field whose data is contained in value.

value

The field's value. This can be a string or Blob (including subclasses such as File). If none of these are specified the value is converted to a string.

filename Optional

The filename reported to the server (a string), when a Blob or File is passed as the second parameter. The default filename for Blob objects is "blob". The default filename for File objects is the file's filename.

Note: If you specify a Blob as the data to append to the FormData object, the filename that will be reported to the server in the "Content-Disposition" header used to vary from browser to browser.

Return value

None (undefined).

Examples

formData.set("username", "Chris");

When the value is a Blob (or a File), you can specify its name with the filename parameter:

formData.set("user-pic", myFileInput.files[0], "chris.jpg");

If the value is not a string or a Blob, set() will convert it to a string automatically:

formData.set("name", 72);
formData.get("name"); // "72"

Specifications

Browser compatibility

See also

• Using FormData objects
• <Form>