div.border 
{
    border: solid 2px black;
    padding:20px;
    width: 300px;
    background-color: #ccc;
}

* html div.border 
{
    width: 344px;
}
div.rulerIE 
{
    width:300px;
    background-color: Red;
}
div.rulerCSS 
{
    width: 344px;
    background-color: Green;
}