IE8 css selector [duplicate]

I’m not going to get in a debate about whether or not this method should be used, but this will let you set specific css attributes for IE8-9 only (note: it is not a selector, so a bit different than what you asked):

Use ‘\0/’ after each css declaration, so:

#nav li ul  {
  left: -39px\0/ !important;
}

And to build off another answer, you can do this to assign variou styles to IE6, IE7, and IE8:

#nav li ul  {
   *left: -7px    !important; /* IE 7 (IE6 also uses this, so put it first) */
   _left: -6px    !important; /* IE 6 */
    left: -8px\0/ !important; /* IE 8-9 */
}

source:
http://dimox.net/personal-css-hacks-for-ie6-ie7-ie8/