CSS Hack: Quick Tip: How to Target IE6, IE7, and IE8 Uniquely with 4 Characters

資料來源： Quick Tip: How to Target IE6, IE7, and IE8 Uniquely with 4 Characters (http://net.tutsplus.com/tutorials/html-css-techniques/quick-tip-how-to-target-ie6-ie7-and-ie8-uniquely-with-4-characters/)

body {
   color: red; /* all browsers, of course */
   color : green\9; /* IE8 and below */
   *color : yellow; /* IE7 and below */
   _color : orange; /* IE6 */
}