strong coupling and web development

We are all well aware of the dangers of strong coupling: for me, the most dangerous being the increased maintenance costs in such a system. Much has been discussed about coupling and measures such as dependency injection are used to help control it.

However, as far as a Google search leads me to believe, but I didn’t search too hard, not much has been said about the strong coupling that can exist between HTML, CSS, and JavaScript files. Maybe I’m doing something wrong, or at least something different, from others but many times in recent weeks I have found that the dependencies between these files can be rather tight and restrictive.

To understand what I’m talking about, let’s take a look at an example. Consider the following snippets of an HTML, CSS, and JavaScript files respectively:

<div id="main_wrapper">
    <div id="content"></div>
#main_wrapper {
    color: #FFFFFF
$('#main_wrapper').attr('color', '#000000');

As you can see the id is referenced in at least three different places. Well so what?

The problem, as I see it, comes from the fact that it is more than likely these files will be maintained by different people. For example, a designer is likely to maintain the HTML and CSS files and a developer the JavaScript file. In the days before JavaScript proliferation, this maybe wasn’t such a problem. However, with the rise of jQuery and its awesomeness the landscape has changed a little.

In fact, jQuery actually compounds the problem, as we have all become accustomed to seeing JavaScript code littered with things like $('#main_wrapper'), i.e. CSS selectors are referenced throughout the code base. What this means is that when the designer changes the structure of the HTML file, or the class names and ids, it can have unexpected side effects.

The easy (part) solution to all this is that when you create ids and classes you never change/remove them or their container – or at least you never change them without searching globally rather than just locally. I’m not sure how restrictive this is though, maybe those with far more experience of this than I do can offer up some more constructive thoughts? Are designers are just not used to such constraints? I dunno?

To me it just seems like a hassle having to keep track of selectors, ids, and classes in so many different places. It seems to go against the spirit of good programmer where we try to localised any side effects when changes are made. With the above way of working this doesn’t seem possible – and combined with the divided level of responsibility between designers and developers, I imagine this causes an increase in the number of bugs and also in the cost of maintenance.

Maybe others don’t see this as an issue at all? Maybe I’m doing designers around the world a disservice? You decide.

At the moment I can’t offer up any better solutions, as I have not really thought about it too much yet. When I do though, I’ll be sure to report back 😀