CSS3中包含几个新的背景属性，提供更大的背景元素控制

background-image:

 .box{background-image:url();background-position:left bottom;}

background-size:

 .box{background-size:100% 100%;}

background-orgin:

 .box{background:border-box|content-box|padding-box}

background-clip:

 .box{background-clip:content-box|padding-box|border-box;}