CSS 100% height with padding/margin
There is a new property in CSS3 that you can use to change the way the box model calculates width/height, it's called box-sizing.
By setting this property with the value "border-box" it makes whichever element you apply it to not stretch when you add a padding or border. If you define something with 100px width, and 10px padding, it will still be 100px wide.
box-sizing: border-box;
See here for browser support. It does not work for IE7 and lower, however, I believe that Dean Edward's IE7.js adds support for it. Enjoy :)
The better way is with the calc()
property. So, your case would look like:
#myDiv {
width: calc(100% - 10px);
height: calc(100% - 10px);
padding: 5px;
}
Simple, clean, no workarounds. Just make sure you don't forget the space between the values and the operator (eg (100%-5px)
that will break the syntax. Enjoy!
I learned how to do these sort of things reading "PRO HTML and CSS Design Patterns". The display:block
is the default display value for the div
, but I like to make it explicit. The container has to be the right type; position
attribute is fixed
, relative
, or absolute
.
.stretchedToMargin {
display: block;
position:absolute;
height:auto;
bottom:0;
top:0;
left:0;
right:0;
margin-top:20px;
margin-bottom:20px;
margin-right:80px;
margin-left:80px;
background-color: green;
}
<div class="stretchedToMargin">
Hello, world
</div>
Fiddle by Nooshu's comment
The solution is to NOT use height and width at all! Attach the inner box using top, left, right, bottom and then add margin.
.box {margin:8px; position:absolute; top:0; left:0; right:0; bottom:0}
<div class="box" style="background:black">
<div class="box" style="background:green">
<div class="box" style="background:lightblue">
This will show three nested boxes. Try resizing browser to see they remain nested properly.
</div>
</div>
</div>