CSS Attribute selectors允许基于属性值选择元素.不幸的是,我几年来没有使用它们(主要是因为它们不被所有现代浏览器支持).不过,我清楚地记得,通过使用类似于以下内容的代码,我能够使用它们来附加图标的所有外部链接：
a[href=http] {
background: url(external-uri);
padding-left: 12px;
}
以上代码不起作用我的问题是：它是如何工作的？如何选择所有< a> href属性以“http”开头的标签？官方的CSS规范(以上链接)甚至没有提到这是可能的.但我记得这样做.
(注意：明显的解决方案是使用类属性进行区分,我想避免这一点,因为我对HTML代码的构建方式影响不大,所有我可以编辑的是CSS代码.)
至于CSS 2.1,见
http://www.w3.org/TR/CSS21/selector.html#attribute-selectors
执行摘要：
Attribute selectors may match in four ways:
[att]
Match when the element sets the "att" attribute,whatever the value of the attribute.
[att=val]
Match when the element's "att" attribute value is exactly "val".
[att~=val]
Match when the element's "att" attribute value is a space-separated list of
"words",one of which is exactly "val". If this selector is used,the words in the
value must not contain spaces (since they are separated by spaces).
[att|=val]
Match when the element's "att" attribute value is a hyphen-separated list of
"words",beginning with "val". The match always starts at the beginning of the
attribute value. This is primarily intended to allow language subcode matches
(e.g.,the "lang" attribute in HTML) as described in RFC 3066 ([RFC3066]).
CSS3 also defines a list of selectors,但the compatibility varies hugely.
还有a nifty test suite显示哪些选择器在您的浏览器中工作.
至于你的例子,
a[href^=http]
{
background: url(external-uri);
padding-left: 12px;
}
应该做的伎俩不幸的是,它不被IE支持.
