htnl box code example
Example 1: border-box css
#example1 {
box-sizing: border-box;
}
Example 2: how to make a box in html
<div style="width:500px;height:100px;border:1px solid #000;">This is a rectangle!</div>
#example1 {
box-sizing: border-box;
}
<div style="width:500px;height:100px;border:1px solid #000;">This is a rectangle!</div>