这在jquery $('#id'，javascript_object);中意味着什么? [英] What does this mean in jquery $('#id', javascript_object);

问题描述

这个$('#id', javascript_object);在jquery中是什么意思.我知道我们可以将第二个参数中的上下文传递给选择器.但是当第二个参数是javascript对象时会发生什么.

what does this $('#id', javascript_object); mean in jquery . I know that we can pass a context in the second parameter to the selector . But what happens when the second parameter is a javascript object .

预先感谢您的帮助.

推荐答案

第二个参数是选择器上下文.它将搜索限制为特定文档对象或特定DOM元素的子代.

The second parameter is the selector context. It restricts searching to a specific document object or the children of a certain DOM element.

默认情况下，选择器从文档根目录开始在DOM中执行搜索.但是，可以使用$()函数的可选第二个参数为搜索提供备用上下文.例如，如果我们希望在回调函数中搜索某个元素，则可以限制该搜索:

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');
});

由于我们将span选择器限制在此上下文中，因此，只有clicked元素内的span才能获得附加类.

Since we've restricted the span selector to the context of this, only spans within the clicked element will get the additional class.

在显示的示例中，您将在javascript_object的子代中搜索ID为id的元素.

In the example you show, you would be searching for the element with the ID id among the children of javascript_object.

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