chrono.js

/* 
Small timer script by Nicolas Torres
(WIP: needs settings & a some few more helpers)

Usage:
<span id="chrono"></span> // set an element
chrono.start() // starts the timer
chrono.toggle() // play or pause the timer
chrono.stop() // stop and reset the timer
*/ 
window.chrono = (function() {
    this.element = document.getElementById('chrono');
    this.ref = false;
    this.wait = localStorage['wait']?parseInt(localStorage['wait']):0;
    this.diff = 0;
    this.pause = false;
    this.write = function(content) {
        if (!content) content = '0:00';
        if (this.element) this.element.innerHTML = content;
        else console.log('Chrono: '+content);
    };
    this.update = function() {
        if (this.ref == 0) return;
        if (this.pause !== false) localStorage['wait'] = this.wait = ((new Date()).getTime() - this.pause);
        else {
            this.diff = ((new Date()).getTime() - this.ref - this.wait)/1000;
            this.write(Math.floor(this.diff/60)+':'+("0"+Math.floor(this.diff%60)).slice(-2));
        }
        requestAnimationFrame(this.update);
    };
    this.toggle = function() {
        if (this.ref == 0) this.start();
        else this.pause = (this.pause === false)?(new Date()).getTime()-this.wait:false;
    };
    this.start = function() {
        if (this.ref > 0) return;
        localStorage['ref'] = this.ref = localStorage['ref']?parseInt(localStorage['ref']):(new Date()).getTime();
        this.update();
    };
    this.stop = function() {
        this.ref = 0;
        this.wait = 0;
        localStorage.clear();
        this.write();
    };
    this.write();
    if (localStorage['ref']) this.start();
    return this;
})();