在什么条件下我们可以使用css * selector？ [英] in what conditions we can use css * selector?

问题描述

在什么条件下我们可以使用css * selector？多少*选择器是有用的？

只能使css重置或破解

 code> * {margin：0; padding：0; } 
  

还是其他有效用途？有没有办法使用* selector来优化css使用* selector？

是否支持所有浏览器？

解决方案

当你想表达一个元素存在，但你不在乎它是什么时，它主要有用。例如：

  #mything * span {color：red; } 
 

选择内部的范围，但不直接跨越 / p>



当您使用 * 作为全局匹配时，您应该谨慎。因为它可以击中你的页面上的每一个（可能成千上万）元素，它一定没有优化; （例如 .thing * 或只是 * ），它使得最多的浏览器选择器引擎的工作比一个更简单的选择器比 .thing 更难。您可以使用一个 * 规则来重置，但使用这些规则并不是一个好主意。

（个人我有点反对 * {margin：0; padding：0;} 修复它影响的方式多于实际需要的元素;真正的问题边框元素'只是列表元素，< form> 真的。一些形式控件也看起来错了，删除了padding。）

in what conditions we can use css * selector? how much * selector is useful?

is it only to make css reset or hack

* { margin: 0; padding: 0; }

or it has other valid useful uses? is there a ways to use * selector to optimize css using * selector?

Is it supported in all browsers?

解决方案

It's mainly useful where you want to express that there's an element present, but you don't care what it is. For example:

#mything * span { color: red; }

selects spans inside mything, but not spans directly inside mything.

You should be sparing about when you use * as a global match. As it could hit every one of the (potentially thousands of) elements on your page it's certainly no optimisation; in particular when it's the last thing in a selector (eg. .thing * or just * alone) it makes most browser selector engines work much harder than an simpler selector like .thing. You can get away with one * rule for resets, but using loads of them isn't a good idea.

(Personally I'm somewhat against the * { margin: 0; padding: 0; } fix. It affects way more elements than it actually needs to; the real ‘problem margin elements’ are just the list elements and <form> really. Some form controls also look wrong with the padding removed.)

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