为了兼容IE各个版本，需要在CSS中添加额外的代码，比如以前常用的_width。之所以工作，是因为浏览器会忽略不能解析的样式规则，因此举个例子来说，把_width写在width下面，对于非IE浏览器会解析到width，而对于IE6来说，会用_width覆盖前面的width规则，从而达到针对IE6浏览器的兼容。对于IE其他版本(6~11)，也存在同样的兼容性处理方法。
下面是一个速查表：
div {
property:value; /* ie 8/9*/
property:value9; /* ie 9*/
*property:value; /* ie 7*/
_property:value; /* ie 6*/
}
IE 6
* html .ie6 {property:value;}
or
.ie6 { _property:value;}
IE 7
*+html .ie7 {property:value;}
or
*:first-child+html .ie7 {property:value;}
IE 6 and 7
@media screen9 {
.ie67 {property:value;}}
or
.ie67 { *property:value;}
or
.ie67 { #property:value;}
IE 6, 7 and 8
@media screen,screen9 {
.ie678 {property:value;}}
IE 8
html>/**/body .ie8 {property:value;}
or
@media screen {
.ie8 {property:value;}}
IE 8 Standards Mode Only
.ie8 { property /***/: value9 }
IE 8,9 and 10
@media screen {
.ie8910 {property:value;}}
IE 9 only
@media screen and (min-width:0) and (min-resolution: .001dpcm) {
// IE9 CSS
.ie9{property:value;}}
IE 9 and above
@media screen and (min-width:0) and (min-resolution: +72dpi) {
// IE9+ CSS
.ie9up{property:value;}}
IE 9 and 10
@media screen and (min-width:0) {
.ie910{property:value9;} /* backslash-9 removes ie11+ & old Safari 4 */}
IE 10 only
_:-ms-lang(x), .ie10 { property:value9; }
IE 10 and above
_:-ms-lang(x), .ie10up { property:value; }
or
@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {
.ie10up{property:value;}}
IE 11 (and above..)
_:-ms-fullscreen, :root .ie11up { property:value; }
