CSS三角箭头应用实践

 用CSS来制作无图片带箭头的DIV方框（此代码比较适合追求纯代码者）
这类效果也可以用图片背景来实现，代码会更简洁
CSS代码：

div.container{position:absolute;

top:30px;

left:40px;

font-size: 9pt;

display:block;

height:100px;

width:200px;

background-color:transparent;

*border:1px solid #666;

}

s{

position:absolute;

top:-20px;

*top:-22px;

left:20px;

display:block;

height:0;

width:0;

font-size: 0;

line-height: 0;

border-color:transparent transparent #666 transparent;

border-style:dashed dashed solid dashed;

border-width:10px;

}

i{position:absolute;

top:-9px;

*top:-9px;

left:-10px;

display:block;

height:0;

width:0;

font-size: 0;

line-height: 0;

border-color:transparent transparent #fff transparent;

border-style:dashed dashed solid dashed;

border-width:10px;

}

.content{

border:1px solid #666;

-moz-border-radius:3px;
-webkit-border-radius:3px;

position:absolute;

background-color:#fff;
width:100%;

height:100%;

padding:5px;

*top:-2px;

*border-top:1px solid #666;

*border-top:1px solid #666;
*border-left:none;

*border-right:none;

*height:102px;

box-shadow: 3px 3px 4px #999;

-moz-box-shadow: 3px 3px 4px #999;

-webkit-box-shadow: 3px 3px 4px #999;

/* For IE 5.5 - 7 */

filter: progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#999999');

/* For IE 8 */

-ms-filter: "progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#999999')";

}

HTML代码：

<div class="container">

<div class="content">

<br>这是框中的文字，可动态显示。高度自动增加，应该不错吧^_^

</div>

<s>

<i></i>

</s>

</div>

效果图：

这次介绍下CSS制作三角箭头

通常，我们做上图那个三角形，一般都是做张图，而且需要两张，因为一般都是下拉菜单的效果，需要有个hover的样式，箭头是反的。那是不是有更好的办法呢，毕竟要用两张图片来解决这么一个小问题太浪费资源了，于是，下面我要用纯CSS的方法来解决这一问题，用到的只需css的一个属性，就是border-width

我们先来看个样式，如果设置元素边框，会怎么样：

似乎看不出什么，让我给四个边框加上不同的颜色吧再看看吧：

是不是发现了些什么？对，让我们把中间的文字去掉吧：

这样，就出现4个三角形了，然后我们如果需要顶部那个三角形，只需要将border的left、right、bottom设置成背景色就行了：

这样，我们需要的三角形就出现了，并且可以设置4个不同方向的了：

样式代码很简单，就几句话：

float: left;

border-style: solid; border-width: 10px;

border-color: #000 #ccc #ccc #ccc;

height: 0;

width: 0;

font-size: 0;

实际应用

比如我们要使用向下的箭头(兼容IE6写法)

HTML代码：

<div class="demo"><span class="bottom-arrow"></span></div>

CSS代码：

.demo{position:relative}

.bottombottom-arrow{

position:absolute;

top:10px;

left:0px;

border-style:solid;

border-width:100px;

border-color:#000000 transparent transparent transparent;/*上边框设置想要的颜色*/

height:0;

width:0;

font-size:0;

_border-color:#000000 tomato tomato tomato ; /*边框透明色 For IE6-*/

_filter:chroma(color=tomato);/*边框透明色 For IE6-*/

}

说明：
这里的演示是用了边框透明色，如果你用不到透明的话，直接设置border-color为你需要的颜色就可以了，免去为了兼容IE6的透明边框滤镜写法
Chroma属性可以设置一个对象中指定的颜色为透明色，它的表达式如下：

Filter：Chroma（color=color)

这个属性的表达式是不是很简单，它只有一个参数。只需把您想要指定透明的颜色用Color参数设置出来就可以了。