CSS HACK for IE6/IE7/IE8/IE9/FF (summary)

Since I installed the official version of IE8.0, I have summarized several basic CSS HACKs. I hope it will be helpful to those who implement DIV+CSS in the front-end layout of web pages.
This article mainly focuses on: IE6+IE7+IE8+IE9+FF

HACK principle : Different browsers recognize different characters differently (after reading the article, you will find that FF and IE8 have exactly the same ability to recognize the following characters)
Commonly used special character recognition table in CSS:
(1) *: IE6+IE7 can recognize *, but standard browsers FF+IE8 cannot recognize *;
(2) !important: Except for IE6, FF+IE8+IE7 can recognize !important.
(3)_: Except for IE6, FF+IE8+IE7 do not support_;
(4)\9: All IE browsers recognize (IE6, IE7, IE8, IE9)
(5)\0: Only valid for IE8

Example :
(1) Differences between FF (IE8) and IE6 and IE7
backgorund:orange; The background color of FF and IE8 will be orange
*backgorund:red; IE6 and IE7 background color will be red
(2) Differences between FF (IE8) and IE6 and IE7
background:orange; FF and IE8 background color will be orange
*background:red !important; IE7 background color will be red
*background:blue; IE6 background color will be blue
(3) Differences between FF (IE8) and IE6 and IE7
background:orange; FF and IE8 background color will be orange
*background:red; IE7 background color will be red
_background:blue; IE6 background color will be blue
(4) Differences between FF and IE6 IE7 E8
color:gray; The font color of non-IE browsers such as FF will be gray
color:red\9; IE8 IE9 font color will be red

You can understand it at a glance :