为什么在$ .get（）回调关闭中捕获的全局变量始终保持相同的值？ [英] Why does a global variable captured in a $.get() callback closure always hold the same value?

问题描述

我在 $。get（）回调中捕获全局变量的值时遇到了一些问题：

相关标记

 < div class =blockid =blog>< / div> ; 
< div class =blockid =music>< / div> 
< div class =blockid =video>< / div> 
  

相关代码

 < code $（'div.block'）。each（function（）{
 
 $ this_id = $（this）.attr（'id'）; 
 $ b $ （$ this_id）; //输出：博客，音乐，视频
 
 $ .get（'test.php'，{id：$ this_id}，函数（数据）{
 
 alert（$ this_id）; //输出：blog，blog，blog（WHY？）
 
 $（'div＃'+ $ this_id）.html（data）; 
 
}）; 
}）; 
  

我试图获取HTML内容并将其插入到每个 i> divs，但是$ this_id 在调用 $。get（）时没有改变。有人可以解释这一点吗？

解决方案

您必须在函数范围内定义 $ this_id ，否则它将默认为一个全局变量。简单地改变它：

  $ this_id = $（this）.attr（'id'）; b 
 
 
 
 
 
  var $ this_id = $（this）.attr（'id'）; 
  

不管怎样，养成显式声明所有变量的习惯是一个好主意......很多更容易跟踪他们。

I'm having a bit of trouble capturing the value of a global variable in my $.get() callback:

Relevant markup

<div class="block" id="blog"></div>
<div class="block" id="music"></div>
<div class="block" id="video"></div>

Relevant code

$('div.block').each(function() {

 $this_id = $(this).attr('id');

 alert($this_id); // outputs: blog, music, video

 $.get('test.php', {id: $this_id}, function(data) {

  alert($this_id); // outputs: blog, blog, blog (WHY?)

  $('div#' + $this_id).html(data);

 });
});

I'm trying to get HTML content and insert it into each of the block divs, but $this_id doesn't get changed inside the call to $.get(). Can anybody explain this?

解决方案

You have to define $this_id within the function scope, or it'll default to being a global variable. Simply change this:

$this_id = $(this).attr('id');

to this:

var $this_id = $(this).attr('id');

It's a good idea to get into the habit of explicitly declaring all of your variables anyway... Much easier to keep track of them that way.

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