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!

[tags]badges,javascript,theartandscienceofjavascript,book,sitepoint[/tags]

It seems that there is a rather annoying group of people sending random emails about text link advertising to bloggers. I’ve got some, and Ed Eliot sitting next to me got the same. This wouldn’t be an issue, after all I think I should get some reward for keeping this up for years and fending off spammers and hacking attempts while I’d really just want to concentrate on what to write here. The crux of the matter is the ridiculous terms and conditions these new kids on the advertising block ask for:

• Can you add a link to the following articles … for the lifetime of the web site
• I will pay you $10-15 dollars for each link as a one-off payment

My first confusion there is “lifetime of the web site”. Does this mean I can shut it down tomorrow and claim it caught a cold and died? Secondly a ONE-OFF payment of $10 for an infinite time of showing an ad a client probably pays you at least $100 a month for?

I appreciate that some people try to get a foothold in a very competitive market like online advertising (and I got an email answer like that when I pointed out the slight discrepancy of what other companies pay for a monthly view vis-a-vis the one-off I could spend in Starbucks on a coffee and a muffin) but please be reasonable and don’t think that people who have high-traffic sites didn’t do research what value a text link from their sites has. We do get punished by Google for adding them, too, and it should be worth our while.

• March 18th, Roosevelt Hotel NYC, US, AjaxWorld – talking about Building large web applications with the YUI
• March 21st – March22nd, Montreal, Quebec – Nurun workshop on Accessibility
• April 3rd, Scotland, Highland Fling, Scotland – Sharing the joy – building badges for distribution
• April 25th (one day shy of my birthday), London, AbilityNet’s “Accessibility 2.0: a million flowers bloom” – right and wrong implementation of accessibility

Planned talks (need confirmation)

• Ajax Experience 2008 – sent in “the human factor in web applications” and “YUI for control freaks” as proposals
• Tech conference about the future of web development in Beijing

Past talks

• February 12th, London Trocadero Beers and innovation #13 – A panel that chats about the changes of relationships between developers and designers (costs £25 though, didn’t know that)
• February 20th, somewhere in Leeds GeekUp – talking about the YUI

This page is not microformatted as I am a lazy bastard and want a WordPress plugin
[tags]talks,publicspeaking,events,christianheilmann,heilmann[/tags]

Following up the success of the data table to Google chart post, and the request in the comments to do the same for YUI charts, go and check the YUIblog today (like, now) and get your fix there:

• Automatic conversion from simple, accessible data tables to YUI Charts

The elevator pitch:

• Create a valid HTML data table
• Add two script tags to the body and a class to each table
• Have tasty pie charts above each of the tables

[tags]tables,accessibility,yui,flash,progressive enhancement[/tags]

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?

[tags]offline,HTML,documents,downloadable articles,JavaScript,versioncontrol,webdevtrick,tutorials[/tags]