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="height: 50px; width: 300px; background-color: rgb(100,100,100);">width = 300px</div>
<div id="test2" style="height: 50px; width: 300px; background-color: rgb(200,200,200); padding: 10px;">width = 300px; padding = 10px</div>