My article on the Separation of Layout and Logic touched on a key point of heavy Javascript use in an Ajax rich environment…the need for separation of Javascript code – namely events – from the HTML. Behaviour was my suggested CSS/Javascript event selector framework.
Behaviour is a stand-alone event framework. You can use it regardless of whether or not you are using Prototype (or some other Ajax/Javascript library) – which is pretty cool. But…if you are using Prototype there is a lot of code duplication between the two libraries. Luckily, Mir.aculo.us has brought event:Selectors to my attention which is causing me to sing a different tune! Justin Palmer, event:Selector’s creator is crediting Behaviour for the idea, but he’s has what Behaviour has done a few steps further.
- event:Selectors is dependant on Prototype which reduces code duplication.
- It has reduced the layer of complexity of event selecting by one layer of abstraction.
- The framework allows concatenation of CSS elements for event assignment.
- Lastly, its added a loaded event that is triggered when an element loads.
Here’s an example of Behaviour event handlining:
var rules = { '#item li': function(element) { Event.observe(element, 'click', function(event) { var element = Event.element(element); element.setStyle('color': '#c00'); }); }, '#otheritem li': function(element) { Event.observe(element, 'click', function(event) { var element = Event.element(element); element.setStyle('color': '#c00'); }); } }; Behaviour.register(rules);
Here’s the equivalent in event:Selectors:
var Rules = { '#item li:click, #otheritem li:click': function(element) { element.setStyle('color': '#c00'); } }; EventSelectors.start(Rules);
Simplification makes me happy. I’m a convert.
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