Using the HTML5 Canvas API, you can do image compression on the frontend.
After reading a file, you can display it, edit it, post it to a server and download.
Get user coordinates using the HTML5 Geolocation API and map using Leaflet.js.
The native FileReader API can be used to read a PDF and create a URL to its contents.
The in-built Date() method can generate an accurate UNIX timestamp.
Date and time objects created using the Date() constructor can be output in various formats.
How to print a number as a string with comma-formatting or other locale-specific styles.