CSS class repetition to increase specificity

为君一笑 提交于 2019-11-27 14:23:57

Yes, it is possible and intentionally so. While this is not mentioned in the CSS2 spec, it is explicitly mentioned in the Selectors 3 spec:

Note: Repeated occurrances [sic] of the same simple selector are allowed and do increase specificity.

Therefore browsers must increase the specificity when encountering repeated simple selectors, as long as the selector is valid and applicable. This not only applies to repeated classes, but also applies to repeated IDs, attributes and pseudo-classes.

Given your code, .qtxt.qtxt.qtxt.qtxt.qtxt will have the highest specificity. The other two selectors are equally specific; combinators have no bearing in specificity calculations at all:

/* 5 classes -> specificity = 0-5-0 */
.qtxt.qtxt.qtxt.qtxt.qtxt

/* 2 classes -> specificity = 0-2-0 */
.qtxt.lalgn

/* 2 classes -> specificity = 0-2-0 */
.lalgn .qtxt

Also, the space in your last selector is the descendant combinator; the child combinator is >.

.qtxt.qtxt.qtxt would have the highest specificity...

http://jsfiddle.net/nXBTp/1/

However, this is only the case if you repeat the class name more times that any other selector, for example:

http://jsfiddle.net/nXBTp/2/

You shouldn't need to hack specificity like this... if you need to force a value, use !important.

易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!