jQuery选择器的多个参数? [英] Multiple Parameters for jQuery selector?

问题描述

我只是看着jQueryUI按钮插件，并注意到了这一点

I was just looking at the jQueryUI button plug-in and noticed this

$("button, input:submit, a", ".demo").button();

我从未见过这样的事情.这就像在一个jQuery选择器中进行多次选择吗?

I never seen something like this. Is this like multiple selects in one jQuery selector?

推荐答案

第二个参数(在您的示例中为".demo")是 context ，基本上，您的选择器被限制为仅匹配a的后代.确定的上下文:

The second argument (".demo" in your example) is the context, basically your selector is restricted to match only descendants of a determined context:

$(expr, context)

等同于使用 find 方法:

Is just equivalent to use the find method:

$(context).find(expr)

请查看 jQuery函数的文档:

选择器上下文

Selector Context

默认情况下，选择器执行其 从DOM开始的DOM搜索 文档根目录.但是， 可以为 通过使用可选的第二个进行搜索 $()函数的参数.为了 例如，如果在回调函数中 我们希望搜索一个元素， 我们可以限制搜索范围:

By default, selectors perform their searches within the DOM starting at the document root. However, an alternate context can be given for the search by using the optional second parameter to the $() function. For example, if within a callback function we wish to do a search for an element, we can restrict that search:

$('div.foo').click(function() {
  $('span', this).addClass('bar');
  // it will find span elements that are
  // descendants of the clicked element (this)
});

还要注意，您发布的"button, input:submit, a"选择器称为多个选择器，并且在那里，您可以指定任意数量的选择器以组合成一个结果，只需用逗号将它们分开即可.

Also notice that the selector you post "button, input:submit, a", is called Multiple Selector, and there you can specify any number of selectors to combine into a single result, just by separating them by a comma.

这篇关于jQuery选择器的多个参数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！