Among the types of CSS selectors, one that is often overlooked is the CSS Adjacent Selector.

Adjacent sibling selectors have the following syntax: E1 + E2, where E2 is the subject of the selector. The selector matches if E1 and E2 share the same parent in the document tree and E1 immediately precedes E2.

The CSS code

h4 + p {
    font-weight: bold;
    color: #F00;

The text below is a simple example of the above code:

This is normal heading 4 text

This is the <p> after the heading. It should be red.

What’s even better is that this seems to work perfectly in IE 7 (UPDATE: it seems that this does not work in IE6, so it will be a bit before this is usable on any large scale. However, it is still good to understand these obscure CSS selectors because you may come across them as a professional, especially if IE8 successfully puts IE6 out of the top 5 browsers), Firefox, Opera, and Safari. Now I know what you’re thinking. Where in the world am I going to use this?

Perhaps we could use something like this to do something to all rows in a table except the first row? What if we knew the next element after an tag was going to be a custom caption that we wanted to place properly underneath our image? The only problem I see is that this couples the HTML and CSS more than we might like sometimes. However, there are many places that probably would benefit from something this simple. Simplicity rules. Now that you know how to use it I have every confidence you can come up with a brilliant use for it.

What ideas do you have to use this CSS gem? What other selectors have you found useful but don’t often see?

Posted on .