浏览器 | 最大值 | 超过最大值后变成 | 最小值 | 小于最小值后变成 | 备注 |
IE6 Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
| IE7 | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
| IE8 | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
| IE9 | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
| IE10 | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
| IE11 | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
Firefox 2 Copy after login | 2147483647 Copy after login | 元素消失 | ? | ? | |
Firefox 3 Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 0 Copy after login | ? | ? | |
| Firefox 29(最新稳定版) | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | -2147483648 | |
Safari 3 Copy after login | 16777271 Copy after login | 16777271 Copy after login | ? | ? | |
Safari 4 Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | ? | ? | |
| Safari 5.1.7(最新稳定版) | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 数值不变 Copy after login Copy after login Copy after login | -2147483648 | 数值不变 | 使用的是webkit内核，所以和chrome一致 |
Chrome 29 Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | -2147483648 | 数值不变 | |
| Chrome 35(最新稳定版) | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 数值不变 Copy after login Copy after login Copy after login | -2147483648 | 数值不变 | chrome允许设置超过最大值、最小值的z-index， 不过超出之后层叠样式会使用最大值和 最小值来计算（比如设置为2147483648时， 会以2147483647计算层叠关系） |
Opera 9 Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | ？ | ？ | |
Opera 21(最新稳定版) Copy after login | 2147483647 Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login Copy after login | 数值不变 Copy after login Copy after login Copy after login | -2147483648 | 数值不变 | 使用的是webkit内核，所以和chrome一致 |
结论：z-index的取值范围为-2147483648 ~~ 2147483647。而C的Int型数据类型的大小也为-2147483648 ~~ 2147483647。说明CSS的z-index在C中是作为INT型计算的。一般z-index都不超过100000，所以基本上不用考虑大小问题。PS:chrome中对于width和height的最大限制为33554428，这个有时间再做吧。参考文章：http://stackoverflow.com/questions/8565821/css-max-z-index-valuehttp://www.puidokas.com/max-z-index/http://stackoverflow.com/questions/491052/mininum-and-maximum-value-of-z-index#answer-491105http://www.quora.com/Cascading-Style-Sheets/Is-there-a-maximum-value-for-z-index
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