我正在做一个任务，我必须建立一个测验应用程序。 我一次只显示一个问题。 用户必须从一组无线电输入中选择4个答案中的一个。 
 
 出于某种原因，它仅在用户选择第一个无线电输入时才有效，其他则无响应。 
 
 这是我的代码： 
 
var counter = 0;
var questions = ["<h3>What is the 9 + 10 </h3>\n\
                   <input type='radio' name = 'radio' class='rad' value ='19'>19\n\
                    <input type='radio' name = 'radio' class='rad' value ='23'> 23\n\
                    <input type='radio' name = 'radio' class='rad' value ='44'>66\n\
                    <input type='radio' name = 'radio' class='rad' value ='1'>123 ",
    "<h3>What is the 5 + 10 </h3>\n\
                   <input type='radio' name = 'radio' class='rad' value ='15'>15\n\
                    <input type='radio' name = 'radio' class='rad' value ='23'> 23\n\
                    <input type='radio' name = 'radio' class='rad' value ='44'>44\n\
                    <input type='radio' name = 'radio' class='rad' value ='1'>12 "
];

document.getElementById("question").innerHTML = questions[counter];
document.querySelector('.rad').addEventListener("change", nextQuestion);

function nextQuestion() {
    console.log(counter);
    counter++;
    document.getElementById("question").innerHTML = questions[counter];
}

I am working on an assignment where I have to build a quiz app. I display questions one at a time. The user has to select one of the 4 answers from a group of radio inputs.
 
For some reason it only works when user selects first radio input, other get no response..
 
Here is my code :
 
var counter = 0;
var questions = ["<h3>What is the 9 + 10 </h3>\n\
                   <input type='radio' name = 'radio' class='rad' value ='19'>19\n\
                    <input type='radio' name = 'radio' class='rad' value ='23'> 23\n\
                    <input type='radio' name = 'radio' class='rad' value ='44'>66\n\
                    <input type='radio' name = 'radio' class='rad' value ='1'>123 ",
    "<h3>What is the 5 + 10 </h3>\n\
                   <input type='radio' name = 'radio' class='rad' value ='15'>15\n\
                    <input type='radio' name = 'radio' class='rad' value ='23'> 23\n\
                    <input type='radio' name = 'radio' class='rad' value ='44'>44\n\
                    <input type='radio' name = 'radio' class='rad' value ='1'>12 "
];

document.getElementById("question").innerHTML = questions[counter];
document.querySelector('.rad').addEventListener("change", nextQuestion);

function nextQuestion() {
    console.log(counter);
    counter++;
    document.getElementById("question").innerHTML = questions[counter];
}

原文：https://stackoverflow.com/questions/47879179