Javascript | 如何使用類名打印第二個元素

Question

如何使用類名“nameAnswer”打印第二個元素。 它說：未定義為什么？

HTML：

<h1 class="nameAnswer" value="dog"></h1>
<h1 class="nameAnswer" value="cat"></h1>
<h1 class="nameAnswer" value="fish"></h1>

JAVASCRIPT：

var count = document.getElementsByClassName("nameAnswer").length;
if(count>1){
var answ = document.getElementsByClassName('nameAnswer'[2]).value;
alert(answ);
}

Answer 1

您將需要對代碼稍作更改

var count = document.getElementsByClassName("nameAnswer").length;
if(count>1){
var answ = document.getElementsByClassName('nameAnswer')[2].getAttribute('value')
alert(answ);
}

Answer 2

試試這個

var count = document.getElementsByClassName("nameAnswer").length;
if(count>1){
  var answ = count[2].value;
  alert(answ);
}

Answer 3

您需要在括號后面加上[2] 。 或者只需執行以下操作：

var nameAnswers = document.getElementsByClassName("nameAnswer");
var count = nameAnswers.length;
if(count > 1){
    var answer = nameAnswers[2].value;
    alert(answer);
}

Answer 4

嘗試這個：

 const childNumber = 2 const el = document.querySelector(`.nameAnswer:nth-child(${childNumber})`) const val = el? el.getAttribute('value'): '-' console.log(val)

 <h1 class="nameAnswer" value="dog"></h1> <h1 class="nameAnswer" value="cat"></h1> <h1 class="nameAnswer" value="fish"></h1>