如何在javascript函数中使用getElementsByClassName？ [英] How to use getElementsByClassName in javascript-function?

问题描述

我不知道如何在javascript中使用多个ID。单个ID和getElementById没有问题，但是一旦我将ID更改为类，并尝试使用getElementsByClassName，该功能将停止工作。我读了关于这个话题的100个帖子;仍然没有找到答案，所以我希望有人在这里知道如何使getElementsByClassName工作。

还有一些我用来测试的简单代码：

  function change（）{
 document.getElementById（'box_one'）。style.backgroundColor =blue; 
} 
 
函数change_boxes（）{
 document.getElementsByClassName（'boxes'）。style.backgroundColor =green; 
} 
 
 
< input name =type =buttononClick =change（document.getElementById（'box_one'））; change_boxes（document.getElementsByClassName 'boxes'））value =点击/> 
 
< div id =box_one>< / div> 
< div class =boxes>< / div> 
< div class =boxes>< / div> 
  

解决方案

getElementsByClassName（） code>返回一个 nodeList HTMLCollection *。你正在试图直接对结果进行操作;你需要遍历结果。

  function change_boxes（）{
 var boxes = document.getElementsByClassName（'boxes '），
i = boxes.length; 
 
 while（i--）{
 boxes [i] .style.backgroundColor =green; 
} 
} 
  





---

* 更新以反映接口

之间的更改

I cant figure out how to use multiple IDs in javascript. No problem with single ID and getElementById, but as soon as i change IDs to class and try using getElementsByClassName the function stops working. Ive read about a 100 post about the topic; still havent found the answer so i hope someone here know how to make getElementsByClassName work.

Heres some simple code that i have used for testing:

function change(){
    document.getElementById('box_one').style.backgroundColor = "blue";
}

function change_boxes(){
    document.getElementsByClassName ('boxes').style.backgroundColor = "green";
}


<input name="" type="button" onClick="change(document.getElementById('box_one')); change_boxes(document.getElementsByClassName('boxes'))" value="Click" />   

<div id="box_one"></div>
<div class="boxes" ></div>
<div class="boxes" ></div>

解决方案

getElementsByClassName() returns a nodeList HTMLCollection*. You are trying to operate directly on the result; you need to iterate through the results.

function change_boxes() {
    var boxes = document.getElementsByClassName('boxes'),
        i = boxes.length;

    while(i--) {
        boxes[i].style.backgroundColor = "green";
    }
}

---

* updated to reflect change in interface

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