1. Child Selector
H1> strong {color: red;} is invalid.
Only H1 strong {color: red;} can be used ;}
The subselector is not supported, but the subselector is supported.
2. sibling Selector
Invalid Li + Li {font-style: bold.
3. limited support for pseudo-class selector
A: Link: visited {color: # FFF;}, only recognizes the last one: visited.
It is best to write in the following order:
A: link {color: Navy ;}
A: visited {color: Gray ;}
A: hover {color: red ;}
A: active {color: yellow ;}
IE6 supports pseudo-class delimiters and is limited to hyperchains.
4 attribute Selector
H1 [Class] {color: Silver;} is invalid.
Not supported above. Eric Meyer's authoritative CSS guide pointed out that I have also verified IE6 SP1/Win XP in mainstream environments.
5. Eric Meyer says that Internet Explorer does not support multi-class delimiters correctly, at least not Internet Explorer 6.
. Warning. Urgent {Background: Silver;} is valid, not invalid.