JavaScript Countdown Timer

I was in search of a JavaScript countdown timer (mainly because I’m too lazy to build it out myself — and because I’m sure millions before me have done the same), but Google wasn’t doing me much good. Most scripts would modify the DOM, directly but not make it easy to programmatically intercept the remaining time.

So, I picked one of the cleanest scripts and cleaned it up a bit.


/**
 * A sweet js countdown timer with a custom callback that gives you a JSON object!
 * Heavily modified code originally found on http://www.ricocheting.com/code/javascript/html-generator/countdown-timer
 *
 * @param string|Date String representation of when to countdown to. Date objects probably work too
 * @param callback Function triggered when the interval has passed
 * @param int Number of milliseconds for the timeout. Defaults to 1000 (1 second)
 *
 * @return object Returns a JSON object with properties: days, hours, minutes, seconds
 */
timer = function(endDate, callback, interval) {
    endDate = new Date(endDate);
    interval = interval || 1000;

    var currentDate = new Date()
        , millisecondDiff = endDate.getTime() - currentDate.getTime() // get difference in milliseconds
        , timeRemaining = {
            days: 0
            , hours: 0
            , minutes: 0
            , seconds: 0
        }
        ;

    if(millisecondDiff > 0) {
        millisecondDiff = Math.floor( millisecondDiff/1000 ); // kill the "milliseconds" so just secs

		timeRemaining.days = Math.floor( millisecondDiff/86400 ); // days
		millisecondDiff = millisecondDiff % 86400;

		timeRemaining.hours = Math.floor( millisecondDiff/3600 ); // hours
		millisecondDiff = millisecondDiff % 3600;

		timeRemaining.minutes = Math.floor( millisecondDiff/60 ); // minutes
		millisecondDiff = millisecondDiff % 60;

		timeRemaining.seconds = Math.floor(millisecondDiff); // seconds

        setTimeout(function() {
            timer(endDate, callback);
        }, interval);
    }
    
    callback(timeRemaining);
}

It’s easy to use! You specify an end date (as a string, though Date object’s should work as well) and pass in a callback that gets triggered at a set interval. The callback receives a JSON object with properties for days, hours, minutes and seconds. You can pass in a custom interval if you want the callback triggered at a different period. Examples below.


timer('2011-12-31', function(timeRemaining) {
	console.log('Timer 1:', timeRemaining);
});

// This will run every minute, instead of every second
timer('2012-12-31', function(timeRemaining) {
	console.log('Timer 2:', timeRemaining);
}, 60000);

Interested? See it in action: http://jsfiddle.net/mjangda/vGv7J/1/

JavaScript Tip: Bust and Disable console.log

Here’s a quick and dirty follow-up to my original Save me from console.log errors. The main improvement to this version is that it includes a way to disable console.log (and related functions), for example, in production environments.

While console.log is awesome, you really don’t want your dirty inner workings littering up the Console (or visible to the user — though, you could make an argument that this is a great way to debug errors in live environments) once your app is deployed.

Note: Firebug can get unhappy sometimes if you try to mess with its console object. But, in theory, this approach should work.


var DEBUG_MODE = true; // Set this value to false for production

if(typeof(console) === 'undefined') {
    console = {}
}

if(!DEBUG_MODE || typeof(console.log) === 'undefined') {
    // FYI: Firebug might get cranky...
    console.log = console.error = console.info = console.debug = console.warn = console.trace = console.dir = console.dirxml = console.group = console.groupEnd = console.time = console.timeEnd = console.assert = console.profile = function() {};
}

[[Prototype]] vs prototype (Peter van der Zee on JSMentors)

Here’s a great explanation (by Peter van der Zee) of the key differences between [[Prototype]] and prototype in JavaScript. It finally makes sense now!

Note: to understand this explanation it would help to know what prototype is/does and how it works.

So we have [[Prototype]] and prototype. You can see prototype as the parent object to which [[Prototype]] (so __proto__) refers to on instances of the constructor. Hah, I’m sure that’s not confusing. So let me give an example :)

var A = function(){};
var a = new A();
log(a instanceof A); // true
log(A.prototype); // object
log(a.prototype); // undefined
log(a.__proto__); // object, in browsers that support the mapping
log(a.__proto__=== A.prototype); // true.

“A” has a prototype property (A.prototype). If you add new properties to that object, they will automagically be available on “a”. “a” has a [[Prototype]] internal property. It refers to A.prototype. It is an essential part of the prototypal chain because it actually determines the next part of the chain. If you change a.[[Prototype]], changes to A.prototype will no longer be reflected on “a”. In fact, all not “own” properties of a will no longer be accessible and are replaced by a new set of properties.

via [JSMentors] Object creation.

FITC Mobile 2010 Presentation: HTML5, CSS3, and other fancy buzzwords

My presentation at FITC Mobile 2010 went better than I expected! The slides are embedded below and can be downloaded here.

Note: the animations in the slideshare version don’t work.

Also, check out some really dumbed down demos I made.

WordPress Tip: Hooking into Widget Save Callback

John Gadbois turned some code I gave him into short and useful write-up on how to hook into AJAX calls triggered when saving widgets. It makes use of jQuery’s Global AJAX event handlers, which allow for some very cool things, especially when you’re working with external libraries that use the jQuery AJAX methods. A future blog post will cover how plugins can use the ajaxSend event to hook into WordPress’ autosave.

jQuery Plugin: HTML5 Inline Data

HTML5 Data Attributes are sexy.

What’s sexier is an easy way to work with these data attributes using jQuery.

Sure, you could do something like:

jQuery('#pancakes').attr('data-type');

But who wants to type the “data-“ prefix over and over again?

So, here’s a quick little plugin I whipped up. It’s probably terrible when it comes to jQuery plugin standards (I do WordPress plugins, not jQuery), but it works. It works as a getter and setter.

Bonus: If you’re using jQuery 1.4.1+, the plugin supports well-formed JSON objects as data attribute values.


/*
* Inline Data - get and set HTML5 data attributes! Yay!
*
* Copyright (c) 2010 Mohammad Jangda (http://digitalize.ca), Vortex Mobile (http://www.vortexmobile.ca)
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/mit-license.php
*
*/

(function($) {
    $.fn.inlinedata = function(name, value) {
        
        var prefix = 'data-';
        var attr = prefix + name;
        var values = []
        
        this.each(function(i) {
            var attrValue;
            
            // Setting values
            if(value) {
                // If an array is passed, the array index should correspond to the collection index
                if($.isArray(value)) {
                    // Check, check, check the index. Because out of bounds exceptions are the devil!
                    if(typeof(value[i]) !== 'undefined')
                        attrValue = value[i];
                    else
                        attrValue = '';
                } else {
                    // Not an array, so we're just giving all the elements the same value
                    attrValue = value;
                }
                this.setAttribute(attr, attrValue);
            } else {
                // Getting values
                attrValue = this.getAttribute(attr);
                
                try {
                    // try parsing as JSON
                    attrValue = jQuery.parseJSON(attrValue);
                } catch(e) { }
            }
            attrValue = (attrValue) ? attrValue : '';
            values.push(attrValue);
        });
        
        if(values.length == 1)
            return values[0]
        
        return values;
    }
})(jQuery);

Usage is simple:














JavaScript Tip: Save me from console.log errors

It’s bound to happen. You build yourself a sweet webapp with some sweet javascript action and you unleash it to the world only to get angry emails yelling, “IT DOESn’T WoRK! FIX iT okAy?” And it’s the darndest problem because it’s happening to both IE and Firefox users (Chrome and Safari users have been silent) and you can’t replicate it.

And then you spend hours trying to figure out the problem to no avail, leaving you scratching that magnificent head of yours with luscious, flowing hair. You just can’t replicate the problem. But then, after hours and days of staring intently at the screen, you find it. It’s a rogue console.log call that you forgot to comment out. And then you spend the remainder of the week chastising yourself for being stupid.

It happens. (To be fair, it’s not your fault that your users don’t have Firebug or IE Developer Tools installed. Blame it on Mozilla/Microsoft.)

But there’s an easy solution. Just copy the following javascript somewhere in your project, and rest easy:


if(typeof(console) === 'undefined') {
    var console = {}
    console.log = console.error = console.info = console.debug = console.warn = console.trace = console.dir = console.dirxml = console.group = console.groupEnd = console.time = console.timeEnd = console.assert = console.profile = function() {};
}

WordPress Plugin: HTML Emails

Tired of all those boring emails that you get from WordPress? Do you dread opening emails from WordPress because plain text and/or over-querystringified links terrify you? Rest easy friend, HTML emails for WordPress are here.

HTML Emails replaces the standard WordPress emails with spruced up versions that simply look good. Sample included below:

New Comment Notification as seen in Gmail

Currently, only comment notifications are HTML-ized (new comment and comment moderation emails), but I’m hoping to add all other email notifications soon (and yes, that includes Multi-Site emails coming with WordPress 3.0).

While I have only tested the emails on Gmail, Gmail on Android, and Outlook, they should work on most email clients (including clients without HTML support). If you’re using a client other than the 3 I’ve listed, I would appreciate an email with info on whether the email looks like it should and works correctly.

Don’t like my design chops? (Go ahead, admit it!) I’ve got you covered! HTML emails makes it easy to fully customize the look and feel of emails sent by WordPress. See the Other Notes section on the Plugin page for details on how to customize emails. More detailed walkthroughs to come.

Grab it from the Plugin Directory or install directly from WordPress (Plugins > Add New, search for HTML Emails).