filelist

FileList is a read‑only DOM interface that represents a collection of File objects. It is created automatically by the browser when a user selects one or more files through an <input type="file"> element or when drag‑and‑drop operations provide file references to a web application. The object behaves like an arrayish list: it has a numeric length property, indexed access to individual File objects, and an item(index) method that returns the file at the given position or null if the index is out of bounds. Unlike a normal array, FileList does not provide array methods such as push, pop, or forEach, although it can be converted to an array with methods such as Array.from() or the spread operator.

Each File object exposed by a FileList contains metadata about the selected file, including its name, size in bytes, MIME type, lastModified timestamp, and a Blob representation of its contents. Scripts can obtain these properties to validate input, display previews, or prepare data for upload. A FileList instance is commonly passed as the files property of a FormData object, enabling multipart/form-data uploads via XMLHttpRequest or the fetch API.

FileList support is widespread across modern browsers and is part of the File API specification defined by the WHATWG. Early versions of Internet Explorer had limited support, but current versions of all major browsers provide full functionality. Because the collection is read‑only, developers must clone the FileList or copy its items into a new array if they need to modify the list during processing.