E[attr]

Matches any E element with the "attr" attribute set (whatever the value). (Source: W3C)

HTML:

1. <p>Lorem ipsum dolor sit amet, consectetur</p>
2. <p class="paragraph">Lorem ipsum dolor sit amet, consefctetur</p>

CSS:

1. p{font-style:normal}
2. p[class]{font-style:italic}

Output:

In the example, the second paragraph should be set in italics.