GitHub - rchristian/pomodoro-clock: Pomodoro countdown timer built with JQuery. Users can customize work session and break times, reset timers, mute audio alerts, and more.
Countdown JavaScript | Countdown clock in JS using HTML & CSS | Countdown Timer with JavaScript - YouTube
Making a jQuery Countdown Timer - Tutorialzine
central control timer using php any jquery or WebSocket OR node.js - Stack Overflow