选择器[class ^ =" span"]有什么作用？ [英] What does the selector [class^="span"] do?

问题描述

我无法弄清楚这是什么：

I can't work out what this is:

http://twitter.github.com/bootstrap/assets/css/bootstrap-1.2.0.min.css

.row [class^="span"] {
  display: inline;
  float: left;
  margin-left: 20px;
}

我理解了风格，但我从来没有见过这个

I understand the style but I've never seen this before

[class^="span"]

推荐答案

这意味着以span开头的类，例如：

This means a class beginning with the word "span", such as:

<div class="spanning"></div>

^ 符号取自正则表达式，其中此符号指字符串的开头。

The ^ symbol is taken from regular expressions, wherein this symbol refers to the beginning of a string.

应该注意，这将检查类属性的开头，而不是类名的开头。这意味着它不匹配所述选择器：

It should be noted that this checks for the beginning of the class attribute, not the beginning of the classname. Which means it will not match said selector:

<div class="globe spanning"></div>

上述元素有两个类，第二个以span开头， class 以globe开头，而不是以span开头，它将不匹配。

The above element has two classes, the second of which begins with "span" - but since the attribute class begins with "globe", not with "span", it will not match.

code> [class * = span] ，它将返回包含span的所有类，但也会返回其他类，例如 wingspan 。

One could use [class*=span], which would return all classes containing span, but that would also return other classes, such as wingspan.

AFAIK，获取以字符串开头的类的方法是使用双选择器：

AFAIK, the way to get classes that begin with a string are to use a double selector:

.row [class^="span"], .row [class*=" span"]{}

这将返回以span开头的类，无论是在属性开头还是在中间。

This will return the class beginning with span, whether at the beginning of the attribute, or in the middle.

我还记得在 DOMParser 使用的本地选择器引擎中使用解决方案。

(I also recall working in a solution in the homegrown selector engines used by DOMParser).

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