nth-child 选择器

jquery代码：

<script type="text/javascript" language="javascript">
		$(function(){
			$(".weui-media-box:nth-child(3n)").addClass("toBottomRight")
			$(".weui-media-box:nth-child(3n+1)").addClass("toBottomRight-deg");
			$(".weui-media-box:nth-child(3n+2)").addClass("toBottomRight-deg2");
		});
</script>

css代码----css3颜色渐变

.toBottomRight {
  background-image: -webkit-linear-gradient(tp bottom right, #4F83BD, #0D4E96);
  background-image: linear-gradient(to bottom right, #4F83BD, #0D4E96);
}

.toBottomRight-deg {
  background-image: -webkit-linear-gradient(tp bottom right, #E55C64, #D0333C);
  background-image: linear-gradient(to bottom right, #E55C64, #D0333C);
}

.toBottomRight-deg2 {
  background-image: -webkit-linear-gradient(tp bottom right, #1BB28F, #0D8A6C);
  background-image: linear-gradient(to bottom right, #1BB28F, #0D8A6C);
}