在一组CSS伪类之后添加换行符

Question

如何在每组两个列表元素之后插入换行符？它不一定需要是HTML <br />,而只需要将接下来的两个元素移动到下一行.决定在这里完全使用CSS/3(通过jQuery).

HTML:

<div id="headline_gallery">
    <ul>
        <li><img src="images/picture1.png" alt="picture1" /></li>
        <li><img src="images/picture2.png" alt="picture2" /></li>
        <li><img src="images/picture3.png" alt="picture3" /></li>
        <li><img src="images/picture4.png" alt="picture4" /></li>
    </ul>
</div>

CSS:

#headline_gallery li:nth-child(4n),#headline_gallery  li:nth-child(4n-1) {
    background:red;
    display:inline;
}

#headline_gallery li:nth-child(4n-2),#headline_gallery  li:nth-child(4n-3) {
    background:blue;
display:inline;
}

Answer 1

我会使用好的旧浮子和第n个子选择器

http://jsfiddle.net/QCcca/

li {
    float: left;
}
li:nth-child(odd) {
    clear: left;
}