web开发（3） 传说的盒模型之border_html/css_WEB-ITnose
大道至简
上一章节我们学会了padding的用法，padding是为我们的文本区域添加内边距，类似于礼品盒的泡沫区域（即保护区域），那么盒子都是有外边的硬纸壳的，这在我们的web开发中会有对应的属性吗？
答案很明显是有的，就是我们今天的主角border。请看下列代码：
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Border</title><style> div { width: 200px; height: 200px; background-color: red; border: 5px solid orange; }</style></head><body><div></div></body></html>
border.png
效果如图所示，橘黄色区域就是我们的border了。再来回想下代码border: 5px solid orange,里边到底是什么意思呢？这行代码等同于下列代码:
/*定义边框宽度*/border-width: 5px;/*定义边框样式*//*solid为实线、dashed为虚线、dotted为点线*/border-style: solid;/*定义边框颜色*/border-color: orange;
如果是分写的话，以上三条语句缺一不可，ok我们可以来分析下我们原来的那条语句了。
- 第一个参数是border-width
- 第二个参数是border-style
- 第三个参数是border-color
我们再来看看下边的代码：
border-top: 1px solid red;border-bottom: 1px solid red;border-left: 1px solid red;border-right: 1px solid red;
没错啊，我们还可以单独为某一个方向设置border，是不是很方便。
注意：我们在使用border的时候会发现盒子的面积变大了，没错的border是外嵌的，它的存在会影响宽高。
创造即永恒，喝茶去……
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