如何使用类名“ nameAnswer”打印第二个元素。它说:undefined为什么?
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);
}
尝试此方法
var count = document.getElementsByClassName("nameAnswer").length;
if(count>1){
var answ = count[2].value;
alert(answ);
}
您需要在括号后面加上[2]
。或只是执行以下操作:
var nameAnswers = document.getElementsByClassName("nameAnswer");
var count = nameAnswers.length;
if(count > 1){
var answer = nameAnswers[2].value;
alert(answer);
}
尝试一下:
const val = document.querySelector('.nameAnswer:nth-child(2)').getAttribute('value')
console.log(val)
<h1 class="nameAnswer" value="dog"></h1>
<h1 class="nameAnswer" value="cat"></h1>
<h1 class="nameAnswer" value="fish"></h1>