a écrit :
The following elements can have focus by default but are not tab stops. These elements can be set as tab stops by setting the tabIndex property to a positive integer. applet, div, frameSet, span, table, td.

/* focusable content: anything w/ tabindex >=0 is focusable */

abbr:focus, acronym:focus, address:focus, applet:focus, b:focus, 

base:focus, big:focus, blockquote:focus, br:focus, canvas:focus, caption:focus,

center:focus, cite:focus, code:focus, col:focus, colgroup:focus, dd:focus,

del:focus, dfn:focus, dir:focus, div:focus, dl:focus, dt:focus, em:focus,

fieldset:focus, font:focus, form:focus, h1:focus, h2:focus, h3:focus, h4:focus,

h5:focus, h6:focus, hr:focus, i:focus, img:focus, ins:focus, 

kbd:focus, label:focus, legend:focus, li:focus, link:focus, menu:focus, 

object:focus, ol:focus, p:focus, pre:focus, q:focus, s:focus, samp:focus, 

small:focus, span:focus, strike:focus, strong:focus, sub:focus, sup:focus, 

table:focus, tbody:focus, td:focus, tfoot:focus, th:focus, thead:focus, 

tr:focus, tt:focus, u:focus, ul:focus, var:focus {

  /* Don't specify the outline-color, we should always use initial value. */

   outline: 1px dotted;

}