Border-Box Demo

Using CSS3 box-sizing so element dimensions remain constant when padding and border added.

by the_voder

HTML

<div id="div1">I have no padding or border</div>
<div id="div2">I have padding and border</div>

CSS

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#div1,
#div2 {
  width: 200px;
  height: 200px;
  background-color: #ddd;
  margin: 10px;
}

#div2 {
  padding: 10px;
  border: red 3px dashed;
}