如果将圆角矩形分割成上中下三个，可实现背景自动增加，但要实现这个效果，需要将圆角矩形分割成三个图片或更多，图片用的过多，影响网速。
圆角矩形可以通过Css来实现，下面有几种不同的CSS效果代码，与大家共享。
样式1：简洁型css圆角矩形
css代码:
.b1,.b2,.b3,.b4,.b1b,.b2b,.b3b,.b4b,.b{display:block;overflow:hidden;}
.b1,.b2,.b3,.b1b,.b2b,.b3b{height:1px;}
.b2,.b3,.b4,.b2b,.b3b,.b4b,.b{border-left:1px solid #999;border-right:1px solid #999;}
.b1,.b1b{margin:0 5px;background:#999;}
.b2,.b2b{margin:0 3px;border-width:2px;}
.b3,.b3b{margin:0 2px;}
.b4,.b4b{height:2px;margin:0 1px;}
.d1{background:#F7F8F9;}
页面代码:
<div>
<b class="b1"></b><b class="b2 d1"></b><b class="b3 d1"></b><b class="b4 d1"></b>
<div class="b d1">
<font style="font-size:26px;color:red; margin:0px 10px;">简洁型css圆角矩形</font>
</div>
<b class="b4b d1"></b><b class="b3b d1"></b><b class="b2b d1"></b><b class="b1b"></b>
</div>
样式2：3D效果css圆角矩形
css代码：
.raised{background:transparent;width:40%;}
.raised h1,.raised p{margin:0 10px;}
.raised h1{font-size:2em;color:#fff;}
.raised p{padding-bottom:0.5em;}
.raised .b1,.raised .b2,.raised .b3,.raised .b4,.raised .b1b,.raised .b2b,.raised .b3b,.raised .b4b{display:block;overflow:hidden;font-size:1px;}
.raised .b1,.raised .b2,.raised .b3,.raised .b1b,.raised .b2b,.raised .b3b{height:1px;}
.raised .b2{background:#ccc;border-left:1px solid #fff;border-right:1px solid #eee;}
.raised .b3{background:#ccc;border-left:1px solid #fff;border-right:1px solid #ddd;}
.raised .b4{background:#ccc;border-left:1px solid #fff;border-right:1px solid #aaa;}
.raised .b4b{background:#ccc;border-left:1px solid #eee;border-right:1px solid #999;}
.raised .b3b{background:#ccc;border-left:1px solid #ddd;border-right:1px solid #999;}
.raised .b2b{background:#ccc;border-left:1px solid #aaa;border-right:1px solid #999;}
.raised .b1{margin:0 5px;background:#fff;}
.raised .b2, .raised .b2b{margin:0 3px;border-width:0 2px;}
.raised .b3, .raised .b3b{margin:0 2px;}
.raised .b4, .raised .b4b{height:2px; margin:0 1px;}
.raised .b1b{margin:0 5px; background:#999;}
.raised .boxcontent{display:block;background:#ccc;border-left:1px solid #fff;border-right:1px solid #999;}
页面代码：
<div class="raised">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>3D圆角矩形</h1>
</div>
<b class="b4b"></b><b class="b3b"></b><b class="b2b"></b><b class="b1b"></b>
</div>
样式3：略带菱形的css圆角矩形
css代码：
.curved {
background:transparent;
width:40%;
}
.curved h1, .curved p {
margin:0 10px;
}
.curved h1 {
font-size:2em;
color:#fff;
}
.curved p {
padding-bottom:0.5em;
}
.curved .b1, .curved .b2, .curved .b3, .curved .b4 {
display:block;
overflow:hidden;
height:1px;
font-size:1px;
}
.curved .b2, .curved .b3, .curved .b4 {
background:#e0cea3;
border-left:1px solid #fff;
border-right:1px solid #fff;
}
.curved .b1 {
margin:0 4px;
background:#fff;
}
.curved .b2 {
margin:0 4px;
height:2px;
}
.curved .b3 {
margin:0 3px;
}
.curved .b4 {
margin:0;
height:1px;
border-width:0 3px 0 3px;
}
.curved .boxcontent {
display:block;
background:#e0cea3;
border:0 solid #fff;
border-width:0 1px;
}
页面代码：
<div class="curved">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>略带菱形的css圆角矩形</h1>
</div>
<b class="b4"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>
样式4 特殊css圆角矩形
css代码：
.pillar {
background:transparent;
width:40%;
}
.pillar h1, .pillar p {
margin:0 10px;
}
.pillar h1 {
font-size:2em;
color:#fff;
}
.pillar p {
padding-bottom:0.5em;
}
.pillar .b1, .pillar .b2, .pillar .b3, .pillar .b4 {
display:block;
overflow:hidden;
font-size:1px;
}
.pillar .b1, .pillar .b2, .pillar .b4 {
height:1px;
}
.pillar .b2, .pillar .b3 {
background:#d66;
border-left:1px solid #fff;
border-right:1px solid #fff;
}
.pillar .b4 {
background:#d66;
border-left:4px solid #fff;
border-right:4px solid #fff;
}
.pillar .b1 {
margin:0 2px;
background:#fff;
}
.pillar .b2 {
margin:0 1px;
border-width:0 1px;
}
.pillar .b3 {
height:2px;
margin:0;
}
.pillar .b4 {
margin:0 2px;
}
.pillar .boxcontent {
display:block;
background:#d66;
border-left:1px solid #fff;
border-right:1px solid #fff;
margin:0 5px;
}
页面代码：
<div class="pillar">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b2"></b><b class="b4"></b>
<div class="boxcontent">
<h1>特殊css圆角矩形</h1>
</div>
<b class="b4"></b><b class="b2"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>
样式5 ：反向css圆角矩形
css代码：
.serif {
background: transparent; width:40%;
}
.serif h1, .serif p {
margin:0 10px;
}
.serif h1 {
font-size:2em; color:#fff;
}
.serif p {
padding-bottom:0.5em;
}
.serif .b1, .serif .b2, .serif .b3, .serif .b4 {
display:block;
overflow:hidden;
font-size:1px;
}
.serif .b1, .serif .b2, .serif .b3 {
height:1px;
}
.serif .b2, .serif .b3 {
background:#fc0;
border-left:1px solid #fff;
border-right:1px solid #fff;
}
.serif .b4 {
background:#fc0;
border-left:1px solid #fff;
border-right:1px solid #fff;
}
.serif .b1 {
margin:0; background:#fff;
}
.serif .b2 {
margin:0 1px;
border-width:0 2px;
}
.serif .b3 {
margin:0 3px;
}
.serif .b4 {
height:2px;
margin:0 4px;
}
.serif .boxcontent {
display:block;
background:#fc0;
border-left:1px solid #fff;
border-right:1px solid #fff;
margin:0 5px;
}
页面代码：
<div class="serif">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>反向css圆角矩形</h1>
</div>
<b class="b4"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>