Syntax
js
append(name, value)
append(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 asFile). If none of these are specified the value is converted to a string. filenameOptional-
The filename reported to the server (a string), when a
BloborFileis passed as the second parameter. The default filename forBlobobjects is "blob". The default filename forFileobjects 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
js
formData.append("username", "Chris");
When the value is a Blob (or a File), you can specify its name with the filename parameter:
js
formData.append("user-pic", myFileInput.files[0], "chris.jpg");
As with regular form data, you can append multiple values with the same name:
js
formData.append("user-pic", myFileInput.files[0], "chris1.jpg");
formData.append("user-pic", myFileInput.files[1], "chris2.jpg");
If the value is not a string or a Blob, append() will convert it to a string automatically:
js
formData.append("name", true);
formData.append("name", 72);
formData.getAll("name"); // ["true", "72"]
Specifications
| Specification |
|---|
| XMLHttpRequest # dom-formdata-append |