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Trond Pettersen on Web Development and Topic Maps

Month: November, 2009

Web Application Development with Ontopia – 1. Installation & Requirements

Introduction

Ontopia is an Open Source application that lets you create, manipulate and navigate information represented in topic maps. It’s also a toolbox for building all sorts of applications. Among the advantages of topic maps driven applications are enhanced navigation and search capabilities.

Ever since Ontopia went Open Source earlier this year, I’ve wanted to give an example of how easy it is to build a web application on top of it.

Through the next couple of blog posts, I’ll try to show exactly how easy this is – and I promise to leave out the unnecessary talk (wont discuss Topic Maps, for instance).

First I’ll “reveal” how to set up and start Ontopia. As this requires very little typing on my part, I’ll quickly move on to discuss what our goal is. Then we’ll have a look at the required data model, before pointing out the kinds of views that our application needs to support — and how to lay this out. Afterwards, we create the limited amount of code needed to get everything up and running. Last, we deploy.

All code will be available for download :)
Read the full post »

Event Delegation with YUI 3.0

Personally I’ve never used the YUI library (yet), but the new event delegation functionality of YUI 3.0 has a very nice look to it:

// Defining simple listeners on each element:
Y.on(“click”, handleClick,
“#container ul li a.profile”);

// Defining listener on a container using the delegate() method:
Y.delegate(‘click’, handleClick,
‘#container’, ‘ul li a.profile’);

[...]

Event delegation in YUI 3 moves the overhead of walking the DOM tree from the loading process to the point of user interaction, and decreases complexity by removing the need to match target elements within the callback. Instead, delegate() tests the event target (e.target) against the selector (‘ul li a.profile’) after the event is fired but before the callback is executed…

More at the YUI Blog.

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