在 jQuery 中将 live() 变成 on()

Turning live() into on() in jQuery(在 jQuery 中将 live() 变成 on())

问题描述

我的应用程序已动态添加下拉菜单.用户可以根据需要添加任意数量.

My application has dynamically added Dropdowns. The user can add as many as they need to.

我传统上使用 jQuery 的 live() 方法来检测这些下拉列表之一何时被 change()ed:

I was traditionally using jQuery's live() method to detect when one of these Dropdowns was change()ed:

$('select[name^="income_type_"]').live('change', function() {
    alert($(this).val());
});

从 jQuery 1.7 开始，我已将其更新为:

As of jQuery 1.7, I've updated this to:

$('select[name^="income_type_"]').on('change', function() {
    alert($(this).val());
});

查看文档，这应该是完全有效的(对吗?) - 但事件处理程序永远不会触发.当然，我已经确认 jQuery 1.7 已加载并运行等.错误日志中没有错误.

Looking at the Docs, that should be perfectly valid (right?) - but the event handler never fires. Of course, I've confirmed jQuery 1.7 is loaded and running, etc. There are no errors in the error log.

我做错了什么?谢谢！

推荐答案

on 文档状态(粗体；)):

The on documentation states (in bold ;)):

事件处理程序仅绑定到当前选定的元素；当您的代码调用 .on() 时，它们必须存在于页面上.

Event handlers are bound only to the currently selected elements; they must exist on the page at the time your code makes the call to .on().

等价于 .live() 会类似于

$(document.body).on('change', 'select[name^="income_type_"]', function() {
    alert($(this).val());
});

虽然最好将事件处理程序绑定到尽可能靠近元素的位置，也就是说，绑定到层次结构中更靠近的元素.

Although it is better if you bind the event handler as close as possible to the elements, that is, to an element being closer in the hierarchy.

更新:在回答另一个问题时，我发现 中也提到了这一点.实时文档:

Update: While answering another question, I found out that this is also mentioned in the .live documentation:

根据其后继方法重写 .live() 方法很简单；这些是所有三种事件附件方法的等效调用的模板:

Rewriting the .live() method in terms of its successors is straightforward; these are templates for equivalent calls for all three event attachment methods:

$(selector).live(events, data, handler);                // jQuery 1.3+
$(document).delegate(selector, events, data, handler);  // jQuery 1.4.3+
$(document).on(events, selector, data, handler);        // jQuery 1.7+

这篇关于在 jQuery 中将 live() 变成 on()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编程学习网！