CSS3 box size
CSS3 box size
CSS3 box-sizing property can set the width and height properties, which include padding (inner margin) and border (border).
Do not use the CSS3 box-sizing property
By default, the width and height of an element are calculated as follows:
width(width) + padding(padding) + border(border) = actual width of element
height(height) + padding(padding) + border(border) = actual height of element
This means that when we set the width/height of an element, the actual displayed height and width of the element will be larger (because the border and padding of the element will also be calculated in width/height).
Although the width and height settings of the two
Example
php中文网(php.cn) 这个是个较小的框 (width 为 300px ，height 为 100px)。
这个是个较大的框 (width 为 300px ，height 为 100px)。
Run and try it
Use this method if you want to get a smaller box And including padding, you have to consider the width of the border and padding.
The box-sizing property of CSS3 solves this problem very well.
Use the CSS3 box-sizing property
The CSS3 box-sizing property includes padding (inside) in the width and height of an element margin) and border (border).
If box-sizing: border-box; is set on the element, padding (padding) and border (border) are also included in width and height:
Example
The following is a simple example of adding the box-sizing: border-box; attribute to two
php中文网(php.cn) 两个 div 现在是一样大小的!
php中文网!
Run and try it
box-sizing: border-box; works better, which is exactly what many developers need.
The following code can display the size of all elements in a more intuitive way. Many browsers already support box-sizing: border-box; (but not all - that's why input and text elements with width: 100%; have different widths).
It is recommended to use box-sizing for all elements:
php中文网(php.cn)
提示： 可以尝试移除样式中的 box-sizing 属性，看看会发生什么。注意移除后部分浏览器 input, textarea, 和 submit 按钮的宽度不一致。
Run and try it
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