How does one target IE7 and IE8 with valid CSS?

I want to target IE7 and IE8 with W3C-compliant CSS. Sometimes fixing CSS for one version does not fix for the other. How can I achieve this?

Solution 1:

Explicitly Target IE versions without hacks using HTML and CSS

Use this approach if you don't want hacks in your CSS. Add a browser-unique class to the <html> element so you can select based on browser later.

Example

<!doctype html>
<!--[if IE]><![endif]-->
<!--[if lt IE 7 ]> <html lang="en" class="ie6">    <![endif]-->
<!--[if IE 7 ]>    <html lang="en" class="ie7">    <![endif]-->
<!--[if IE 8 ]>    <html lang="en" class="ie8">    <![endif]-->
<!--[if IE 9 ]>    <html lang="en" class="ie9">    <![endif]-->
<!--[if (gt IE 9)|!(IE)]><!--><html lang="en"><!--<![endif]-->
    <head></head>
    <body></body>
</html>

Then in your CSS you can very strictly access your target browser.

Example

.ie6 body { 
    border:1px solid red;
}
.ie7 body { 
    border:1px solid blue;
}

For more information check out http://html5boilerplate.com/

Target IE versions with CSS "Hacks"

More to your point, here are the hacks that let you target IE versions.

Use "\9" to target IE8 and below.
Use "*" to target IE7 and below.
Use "_" to target IE6.

Example:

body { 
border:1px solid red; /* standard */
border:1px solid blue\9; /* IE8 and below */
*border:1px solid orange; /* IE7 and below */
_border:1px solid blue; /* IE6 */
}

Update: Target IE10

IE10 does not recognize the conditional statements so you can use this to apply an "ie10" class to the <html> element

<!doctype html>
    <html lang="en">
    <!--[if !IE]><!--><script>if (/*@cc_on!@*/false) {document.documentElement.className+=' ie10';}</script><!--<![endif]-->
        <head></head>
        <body></body>
</html>

Solution 2:

I would recommend looking into conditional comments and making a separate sheet for the IEs you are having problems with.

 <!--[if IE 7]>
   <link rel="stylesheet" type="text/css" href="ie7.css" />
 <![endif]-->

Solution 3:

The answer to your question

A completely valid way to select all browsers but IE8 and below is using the :root selector. Since IE versions 8 and below do not support :root, selectors containing it are ignored. This means you could do something like this:

p {color:red;}
:root p {color:blue;}

This is still completely valid CSS, but it does cause IE8 and lower to render different styles.

Other tricks

Here's a list of all completely valid CSS browser-specific selectors I could find, except for some that seem quite redundant, such as ones that select for just 1 type of ancient browser (1, 2):

/******  First the hacks that target certain specific browsers  ******/
* html p                        {color:red;} /* IE 6- */
*+html p                        {color:red;} /* IE 7 only */
@media screen and (-webkit-min-device-pixel-ratio:0) {
    p                           {color:red;}
}                                            /* Chrome, Safari 3+ */
p, body:-moz-any-link           {color:red;} /* Firefox 1+ */
:-webkit-any(html) p            {color:red;} /* Chrome 12+, Safari 5.1.3+ */
:-moz-any(html) p               {color:red;} /* Firefox 4+ */

/****** And then the hacks that target all but certain browsers ******/
html> body p                  {color:green;} /* not: IE<7 */
head~body p                   {color:green;} /* not: IE<7, Opera<9, Safari<3 */
html:first-child p            {color:green;} /* not: IE<7, Opera<9.5, Safari&Chrome<4, FF<3 */
html>/**/body p               {color:green;} /* not: IE<8 */
body:first-of-type p          {color:green;} /* not: IE<9, Opera<9, Safari<3, FF<3.5 */
:not([ie8min]) p              {color:green;} /* not: IE<9, Opera<9.5, Safari<3.2 */
body:not([oldbrowser]) p      {color:green;} /* not: IE<9, Opera<9.5, Safari<3.2 */

Credits & sources:

http://css-tricks.com/snippets/css/browser-specific-hacks/
https://en.wikipedia.org/wiki/CSS_hack
http://www.webdevout.net/css-hacks
MDN: :first-child; :root; :first-of-type; :not(); :any(); * ~ *