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File APIs
Work with files, blobs, and form data

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Modern browsers provide APIs for working with files directly in JavaScript. These APIs enable features like file uploads, drag-and-drop file handling, and reading file contents without server round-trips.

In this unit, you’ll learn how to work with files in the browser. We’ll cover the File API for accessing file metadata and contents, the FileReader API for reading file data, handling file uploads and drag-and-drop interactions, and working with Blobs for binary data.

Understanding these APIs is essential for building applications that handle file uploads, image previews, client-side file processing, and other file-based interactions.

Lessons in this unit:

0: ▶︎ Introduction
1: The File object
2: FileList
3: FileReader
4: Blob
5: FormData
6: Accept only images in file input
7: Check if checkbox is checked
8: Reset a form
9: File upload with server handling
10: Drag and drop file upload
11: Validating file size before upload