Content based CSS: -link-*

This is the 3rd in a series of posts about writing CSS for HTML based on the content of selectors and not just the selectors themselves. As in our first article, we will be discussing how Hitch lets you use ideas currently drafted in CSS Selectors Level 4, right now.

It is frequently the case that we want to style the links in our site according to the level that they correspond to in the URL path – the information architecture.

For example the URL path /2012/05 is important because it represents a month and /2012/05/05 is important because it represents a day. The markup for these is very simple:

<a href="/2012">View 2012</a> 
<a href="/2012/05">View May</a> 
<a href="/2012/05/05">View May 5th</a>

With the current CSS standards there is no way to apply a style based on the path nesting. Today, we attempt to achieve something like this by attaching related classes or impose additional structures. CSS Selectors Level 4 addresses this and once again, Hitch lets you realize the benefit today…

Simply require the hitch and then use it:

 /* add some support for link selectors */ 
@-hitch-requires http://www.hitchjs.com/use/bkardell.links/1.js; 

/* links with /-- should be black */ 
a:-links-local(0) { color: #000000; } 

/* links with /--/-- should be blue */ 
a:-links-local(1) { color: #336699; } 

/* links with /--/--/-- should be gray */ 
a:-links-local(2){ color: #333333; }

With the Link Pseudo Class filters you can specify a style for any number of nested paths and even base the style on fragment identifiers in the URL of the link.

Selectors Level 4 also allows us to select an anchor if it is currently the target in the browser (matches the #hash). Hitch can give you similar capabilities now using the same hitch we already required. To illustrate, given the following markup:

<a name="Summary">View 2012 Summary</a>

You can style it like this:

/* the current target's background should be yellow. */ 
a:-links-target(){ background-color : yellow; }

If the page URL is http://example.com/index.html#Summary then that link’s background would be colored yellow.

The CSS rules are subtly different (but still very standard) while the functionality is extremely new and currently not doable without Hitch.

Doesn’t that feel better? Take a look at Hitch for more expressive CSS!

Note: Hitch is a rather new project. It has amazing potential and also a few things yet to be built. It’s open sourced and available on Github: https://github.com/bkardell/Hitch/. Fork it. Change how CSS works!

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