问题
Chained pseudo-selectors do not seem to work in IE8 on Windows XP. Is there any documentation about this?
I'm developing a website using Selectivizr in order to use CSS3 selectors, but a style such as this doesn't work in IE8, whereas it works everywhere else (unsurprisingly):
span:last-child:after {content: "foobar";}
回答1:
This is not a bug, it's due to the fact the the selector doesn't match natively.
A simple selector is either a type selector or universal selector followed immediately by zero or more attribute selectors, ID selectors, or pseudo-classes, in any order. The simple selector matches if all of its components match.
The simple selector in this case is either span:first-child, which matches natively in IE8, or span:last-child, which does not.
One pseudo-element may be appended to the last simple selector in a chain, in which case the style information applies to a subpart of each subject.
Appending :after to span:first-child is a match, while appending it to span:last-child is not, and since Selectivizr is a post-processor, it comes too late to save the day. Perhaps a pre-processor would have better luck.
来源：https://stackoverflow.com/questions/11577639/chained-pseudo-selectors-in-ie8