Demo for the invalid interpretation of the CSS box model by internet explorer < 6
[http://search.mpi-sb.mpg.de/markus/examples/box-modell/test1.php Test 1]
[http://search.mpi-sb.mpg.de/markus/examples/box-modell/test2.php Test 2 (quirks mode)]
style.width versus offsetWidth
style.width is a read/write property of an element and is the width of the content area of the object.
offsetWidth is a read-only property and means the effective width of the element including padding of the element.
Example:
<div id="test1" style="300px;">width = 300px</div>
<div id="test2" style="width: 300px; padding: 10px;">width = 300px; padding = 10px</div>
var div1 = document.getElementById('test1');
var div2 = document.getElementById('test2');
div1.width: 300px
div2.width: 300px
div1.offsetWidth: 300px
div2.offsetWidth: 320px // if box model is interpreted correctly; not IE < 6 / IE quirks mode