input:focus for Internet Explorer

The :focus class can be used to apply styles to a page element that receives focus. So, for example, if you wanted the background color of input boxes to change when they are in use by the user, you can simply do:
input:focus { background: orange; }

But this does not work for IR and hence

select:focus, textarea:focus, input.sffocus {

border: 1px solid #b2d1ff;  background-color: yellow; color: blue;

}

Ref: http://www.htmldog.com/articles/suckerfish/focus/