​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数组</h1>
​
<p>检查数组中的所有答案是否相同。</p>
​
<p id="demo"></p>
​
<script>
const survey = [
  { name: "Bill",   answer: "Yes"},
  { name: "Steve", answer: "Yes"},
  { name: "David",   answer: "Yes"},
  { name: "Elon",  answer: "No"}
];
​
document.getElementById("demo").innerHTML = survey.every(isSameAnswer);
​
function isSameAnswer(el,index,arr) {
  // 为第一个元素返回 true
  if (index === 0){
    return true;
  }
  else {
  // 比较前一个元素的值
    return (el.answer === arr[index - 1].answer);
  }
}
</script>
​
</body>
</html>
​