JavaScript增加变量 | JavaScript增加变量

本文介绍了JavaScript增加变量的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想为类在每个循环中使用 this ：

  $（。content）。each（function（index）{
 this.id ='content_'+ index; 
}）;

否则，您将选择具有类 .content

JS的唯一方法：
$ b $

  var content = document .querySelectorAll（ '内容'）; 
 
 [] .forEach.call（content，function（item，index）{
 item.id =content_+（index + 1）; 
}）;

ES6 / ES2015语法：

  let content = document.querySelectorAll（'。content'）; 
 
 [] .forEach.call（content，（item，index）=> item.id =`content _ $ {（index + 1）}`）;

I want to add ID to each element of class .content, and I want each ID to have integer increase by 1. Example:

<div class="content" id="content_1"></div>
<div class="content" id="content_2"></div>

etc. I wrote code which looks like this:

var number = 1;
$(".content").each(function() { 
    $('.content').attr('id', 'content_' + number);
    number++;
});

This code adds content_2 to both of them rather than content_1 and content_2, if I have 3 elements with .content class all of them will have an ID of content_3

Any ideas how I could fix that?

解决方案

Use this in the each loop :

$(".content").each(function(index) { 
    this.id = 'content_' + index;
});

Otherwise you are selecting all the elements with class .content

JS only approach:

var content = document.querySelectorAll('.content');

[].forEach.call(content, function(item, index) {
  item.id = "content_" + (index+1);
});

ES6/ES2015 syntax:

let content = document.querySelectorAll('.content');

[].forEach.call(content, (item, index) => item.id = `content_${(index+1)}`);

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