>之间有功能上的区别吗? *:第一个孩子和> :第一个孩子? [英] Is there a functional difference between > *:first-child and > :first-child?

问题描述

在编写代码块时，我注意到在一个地方我写了> :first-child，后来又写了> *:first-child.这两个功能块都可以正常工作，但是两者之间有区别吗?

Writing a block of code, I noticed that in one place I wrote > :first-child and later on > *:first-child. Both blocks appear to be functional, but is there a difference between the two?

推荐答案

即使我们考虑性能，它们也是相同的.从规范中我们可以阅读

They are identical even if we consider performance. From the specification we can read

如果用*表示的通用选择器(即没有名称空间前缀)不是简单选择器选择器序列的唯一组成部分，或者不是紧随其后的是伪元素，那么* 可以省略并暗示通用选择器的存在.

If a universal selector represented by * (i.e. without a namespace prefix) is not the only component of a sequence of simple selectors selectors or is immediately followed by a pseudo-element, then the * may be omitted and the universal selector's presence implied.

因此，为浏览器编写> :first-child的含义应与> *:first-child相同.

So writing > :first-child should mean the same as > *:first-child for the browser.

您还可以阅读

注意:建议不要省略* ，因为这样可以减少例如div :first-child和div:first-child之间的潜在混淆.在这里，div *:first-child更具可读性.

Note: it is recommended that the * not be omitted, because it decreases the potential confusion between, for example, div :first-child and div:first-child. Here, div *:first-child is more readable.

因此，这不仅是优先事项，而且还有助于避免混乱并提高代码的可读性.

So it's not only a matter of preference but it helps avoid confusion and make the code more readable.

在新的分隔符中，我们还可以阅读:

In the new sepcification we can also read:

除非元素没有特征，否则通用选择器的存在对元素是否与选择器匹配没有影响.

和

注意:在某些情况下，添加通用选择器可以使选择器更易于阅读，即使它对匹配行为没有影响.例如，div :first-child和div:first-child很难一目了然，但是将前者写为div *:first-child会使区别显而易见.

Note: In some cases, adding a universal selector can make a selector easier to read, even though it has no effect on the matching behavior. For example, div :first-child and div:first-child are somewhat difficult to tell apart at a quick glance, but writing the former as div *:first-child makes the difference obvious.

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