how to create border box in html code example
Example 1: how do i make a boxin html
<div style="width:500px;height:100px;border:1px solid #000;">This is a rectangle!</div>
Example 2: border-box css
#example1 {
box-sizing: border-box;
}
Example 3: css box model
MDN (Mozilla Developer Network)
Probably the best place for an in-depth explanation of
web related technologies.
See the link below regarding the CSS BOX MODEL