或者你可以在字符串中使用转义字符(\)使用引号 - 在线编辑器

          <script>
  var carname1 = "Volvo XC60";
  var carname2 = 'Volvo XC60';
  var answer1 = 'It\'s alright';
  var answer2 = "He is called \"Johnny\"";
  var answer3 = 'He is called "Johnny"';
  document.write(carname1 + "<br>")
  document.write(carname2 + "<br>")
  document.write(answer1 + "<br>")
  document.write(answer2 + "<br>")
  document.write(answer3 + "<br>")
</script>
        