Box-Sizing属性用于更改元素的高度和宽度。从CSS2开始，box属性的工作方式如下所示-
width + padding + border = actual visible/rendered width of an element's box height + padding + border = actual visible/rendered height of an element's box
要了解box-sizing属性，让我们看一个示例：
<html>
<head>
<style>
.div1 {
width: 300px;
height: 100px;
border: 1px solid blue;
box-sizing: border-box;
}
.div2 {
width: 300px;
height: 100px;
padding: 50px;
border: 1px solid red;
box-sizing: border-box;
}
</style>
</head>
<body>
<div class = "div1">nhooo.com</div></br>
<div class = "div2">nhooo.com</div>
</body>
</html>