Using the HTML5 Canvas API, you can do image compression on the frontend.
Create a download indicator by reading the body of the response.
There is no native expiration option but it can be implemented using timestamps.
Pass a function through localStorage using the Function constructor object.
Allow your users to download any fetchable JSON file in CSV format.
Learn how to track progress and upload a CSS progress bar.
After reading a file, you can display it, edit it, post it to a server and download.
You'll want to push checkbox values into an array only if they are checked.