CSS 属性选择器备忘

再次强烈谴责 W3School，写的根本就是错的，而且怎么发邮件也不改过来。

选择器	效果
[attr]	el.attr !== undefined
[attr=value]	el.attr === 'value'
[attr^=value]	el.attr.startsWith('value')
[attr$=value]	el.attr.endsWith('value')
[attr*=value]	el.attr.includes('value')
[attr~=value]	el.attr.split(' ').includes('value')
[attr|=value]	[attr=value]或[attr^=value-]