与(first)结合使用时find()和children()之间的jQuery差异 [英] jQuery difference between find() and children() when combined with :first

问题描述

在回答以下jQuery问题的过程中需要有关优化以下jquery代码的帮助，我偶然发现了另一个问题大约.find()和.children().

In the process of answering the following jQuery question Need help in Optimizing the below jquery code , I stumbled across another question about .find() and .children().

问题是，给了四个ID为州，城市，分支，分支地址的选择框，以将其删除除了每个选择框的第一个选项以外的所有选项.

The question was, given four selectboxes with ids state, city, branch, branchAddress, to remove all but the first option for each select boxes.

已经发布了几个答案.其中有:

There has been several answers posted. Among those were :

1. $('#state,#city,#branch,#branchAddress').children('option:not(:first)').remove();
2. $('#state,#city,#branch,#branchAddress').children('option:not(:first-child)').remove();
3. $('#state,#city,#branch,#branchAddress').find('option:not(:first)').remove();

1. $('#state,#city,#branch,#branchAddress').children('option:not(:first)').remove();
2. $('#state,#city,#branch,#branchAddress').children('option:not(:first-child)').remove();
3. $('#state,#city,#branch,#branchAddress').find('option:not(:first)').remove();

根据此js小提琴( http://jsfiddle.net/QkNRf/1/)

解决方案2和3似乎运行良好.

Solution 2 and 3 seem to work perfectly.

如果有人可以指出我错过的内容，或者向我解释为什么解决方案3在解决方案1无效的地方工作，我会很高兴.

I would be glad if someone could point me what I missed, or explain to me why solution 3 works where solution 1 does not.

推荐答案

所有其他答案都是正确的，但我认为文档中解释示例1为何失败以及数字3为何起作用的重要部分是有效地.children()过滤前一个选择器的结果，.find()将执行选择器上下文搜索，因此(我假设)它将在所有4个上下文中执行'option:not(:first)'搜索并整理结果，而.children()首先将整理结果，然后使用'option:not(:first)'进行过滤，从而有效地去除了除第一个以外的所有内容...

All the other answers are correct but I think the important part in the doc that explains why example 1 fails and why number 3 works is that while .children() effectively filters the results from the previous selector, .find() will perform selector-context search, so (I assume) it will perform the 'option:not(:first)' search in all 4 contexts and collate the results, while .children() will first collate the results and then filter using 'option:not(:first)' effectively removing all but the very first...

在这种情况下，搜索的深度无关紧要.

The depth of search is irrelevant in this case.

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