Today was a great day: I finally got my Macbook Pro to work with, got myself one of those fancy new slick keyboards and went for it answering a lot of emails. It is amazing how many more emails you can answer when you don’t have to wait for virus scans in the background and Outlook to get a move on.

Not only did I get some good leeway on what I am going to do this year (amongst other things a trip to Beijing to talk to developers about best practices and going back to Germany to talk to Flash developers), I also finally got some other answers I have been waiting for.

To cut it short, I am now not only sneakily blogging for the Yahoo Developer Network blog but was asked to contribute more often. What is even more surprising (considering my history of snide comments there) is that I am now also blogging on Ajaxian.

So if you have some good JavaScript/Ajax or general web development stuff that needs coverage, please drop me a line. I am available here (either via comment or email), on twitter or pownce.

I love the idea of being able to reach a lot of readers and developers through very successful and large channels and it shows me once again how powerful the web is as a media. When I worked as a radio journalist, this wouldn’t have been possible as everything I did had to be connected to my employer exclusively :)

My latest contribution to the ink-on-dead-tree media is a chapter for Sitepoint’s new book
The Art and Science of JavaScript. I’ve been giving details about the history and the contents of the book in detail in a blog post on the Yahoo Developer Blog and while it has been out for a while I just got my free copies today, hence the delay.

My chapter in detail covers how you can build a badge to display information you stored on another site in yours without having to resort to a server side solution or slow down your site. All the magic happens after the page has been loaded and if there is no JavaScript available, visitors will still see a link to the same online resource.

It is a detailed explanation of the rationale and script that feeds my del.icio.us plugin for wordpress shown below:

[delicious:My links about JavaScript,codepo8,10,javascript]

Whilst not the flashiest of the chapters I hope that people can learn something about APIs, REST and dynamic script node generation from it.

I was personally very positively surprised by the quality of the book itself: the full colour print, typography and iconography are very nice. The only thing that is missing is an author name or short bio on the chapter start page, it is a bit tricky to know who did what. Well done Sitepoint!

When you write tutorials and you want people to use them wherever they are it is a good idea to offer the HTML documents as a zip for downloading. The benefit to the end user is that they don’t need to be online to look something up (I for example have the HTML 4.01 documents on my machine as HTML documents). The drawback is that the documents could be outdated without the user knowing – even when they are online while watching them.

Now, I pondered a bit about this and wondered if something like this wouldn’t be a solution:

• You add a version number to the title of each document.
• You add a remotely hosted versions.js script at the end of each document.
• This script has a JSON object with the version information of each document and compares the file name and version.
• If the version is outdated, it generates an error message that gets shown to the user.

You can try it out by downloading the two demo documents un-zip them and open them on a computer that is connected to the internet. The second document linked from the first one should be outdated.

The source of versions.js

(checkversion = function(){

// change as fit

var versions = {

‘documentexample.html’:’1.0’,

‘documentexample2.html’:’2.0’

};

var errorID = ‘versionerror’;

var errorMessage = ‘This document is outdated, please go to the homepage to download the new version!’;


	
// checking code

var d = document;

// get the version number

var cv = d.title.match(/(version (.*))$/);

// get the file name

var cn = window.location.href.split(‘/’);

cn = cn[cn.length-1].split(‘#’)[0];

// check and create error message if there is a mismatch

if(cv[1] && versions[cn]){

if(versions[cn] !== cv[1]){

if(!d.getElementById(errorID)){

var m = d.createElement(‘div’);

m.id = errorID;

m.appendChild(d.createTextNode(errorMessage));

d.body.insertBefore(m,d.body.firstChild);

}
	
}

}
	
}());

You could create both the titles and the JSON object in versions.js on the backend automatically by scanning the titles or from a version control system. What do you think?

Google have lately been praised for their chart API and my esteemed colleague Ed Eliot has a workaround for its restrictions in terms of caching and server hits.

I played around a bit with it and thought it very cool but it felt a bit clunky to add all these values to a URL when they could be in the document for those who cannot see pie charts. This is why I wrote a small script that converts data tables to charts using the API and a wee bit of JavaScript.

Using this script you can take a simple, valid and accessible data table like the following and it gets automatically converted to a pie chart.

Browsers

Browser
Percent


Firefox
60
MSIE
25
Opera
10
Safari
5

Simply add the script to the end of the body and it’ll convert all tables with a class called “tochart”. You can define the size (widthxheight) and the colour as a hexadecimal triplet as shown in this example. If you leave size and colour out, the script will use presets you can alter as variables in the script itself.

What about data tables from charts?

As Victor of the Yahoo! Accessibility group asked for the other way around, this is now also possible. When you use the verbose data mode for the charts and add the class “totable” to the image the script will generate a data table preceeding the image and null out the alternative text. For example:

The tables have a class called “generatedfromchart” which you can use to move them off-left if needed.

Check out the demo page and download the script with the demo page and CSS to have a go with it yourself. Of course, all is licensed creative commons, so go nuts.

Useful? Please comment if you want something extra or wonder how the script works.

Jetlagged like hell and confused I just arrived back from my holiday in Hong Kong, fired up my computer at home and realized that today it was my turn to say something on the advent calendar sites of the web:

• 24 ways – Keeping JavaScript dependencies at bay (English)
• Webkrauts – Große JavaScript Applikationen leicht gemacht (Deutsch)

The article describes a small and easy framework to create a modular JavaScript application that loads dependencies on demand and still gives you full control over what has already been loaded.

This is heavily inspired by the YUI config object and my talk at ajaxWorld East in March will deal with a similar topic.