如何实现按下Escape键关闭模态弹窗及隐藏首图上一页按钮

核心修改点 #

• 新增键盘事件监听实现ESC键关闭模态框
• 调整showSlides函数逻辑，实现首张图片对应弹窗自动隐藏上一页按钮
• 修复原有代码中标题赋值异常、标签嵌套不规范、重复ID导致的运行报错问题

完整JavaScript代码

function openModal() {
  document.getElementById("myModal").style.display = "block";
}

function closeModal() {
  document.getElementById("myModal").style.display = "none";
}

// 新增ESC键关闭模态框逻辑
document.addEventListener('keydown', function(e) {
  const modal = document.getElementById("myModal");
  // 仅当模态框处于显示状态时响应ESC按键
  if (e.key === 'Escape' && modal.style.display === 'block') {
    closeModal();
  }
})

var slideIndex = 1;
showSlides(slideIndex);

function plusSlides(n) {
  showSlides(slideIndex += n);
}

function currentSlide(n) {
  showSlides(slideIndex = n);
}

function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  var prevBtn = document.querySelector('.prev');
  var captionText = document.getElementById("caption");
  if (n > slides.length) {
    slideIndex = 1
  }
  if (n < 1) {
    slideIndex = slides.length
  }
  for (i = 0; i < slides.length; i++) {
    slides[i].style.display = "none";
  }
  slides[slideIndex - 1].style.display = "block";
  // 新增首屏隐藏上一页按钮逻辑
  prevBtn.style.display = slideIndex === 1 ? 'none' : 'block';
  // 修复标题赋值异常问题
  const currentImg = slides[slideIndex - 1].querySelector('img');
  captionText.innerHTML = currentImg.alt || slides[slideIndex - 1].querySelector('p').innerText;
}

完整CSS代码

.modal {
  width: 58%;
  height: 100%;
  top: 0;
  position: fixed;
  display: none;
  background-color: rgba(22, 22, 22, 0.5);
  margin-left: 300px;
  max-width: 779px;
  min-width: 779px;
}

.modal-content {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
}

.mySlides {
  display: none;
}

.close {
  position: relative;
  color: #f1f1f1;
  font-size: 40px;
  font-weight: bold;
  transition: 0.3s;
  left: 584px;
  top: 90px;
}

.close:hover,
.close:focus {
  color: #999;
  text-decoration: none;
  cursor: pointer;
}

.cursor {
  cursor: pointer;
}

.prev {
  cursor: pointer;
  position: relative;
  top: -149px;
  padding: 16px;
  margin-top: -50px;
  color: white;
  font-weight: bold;
  font-size: 20px;
  border-radius: 0 3px 3px 0;
  user-select: none;
  -webkit-user-select: none;
  left: -10%;
}

.next {
  cursor: pointer;
  position: relative;
  top: -149px;
  padding: 16px;
  margin-top: -50px;
  color: white;
  font-weight: bold;
  font-size: 20px;
  border-radius: 0 3px 3px 0;
  user-select: none;
  -webkit-user-select: none;
  left: 600px;
}

完整HTML代码

<!DOCTYPE html>
<html>
<head>
  <title>Calcutta Public School > Photogallery</title>
</head>
<body>
  <div class="row">
    <div class="column">
      <p align="center"><img src="https://source.unsplash.com/user/erondu/1600x900" alt="Annual function" width="250" height="164" onclick="openModal();currentSlide(1)" class="hover-shadow cursor"></p>
    </div>
    <div class="column">
      <p align="center"><img src="https://source.unsplash.com/collection/190727/1600x900" alt="Annual function" width="250" height="164" onclick="openModal();currentSlide(2)" class="hover-shadow cursor"></p>
    </div>
  </div>

  <div id="myModal" class="modal">
    <div class="modal-content">
      <span class="close cursor" onclick="closeModal()">&times;</span>

      <div class="mySlides">
        <img src="https://source.unsplash.com/user/erondu/1600x900" style="width: 98%;position: relative;left: 10px;top: 109px;">
        <p id="caption" style="padding-bottom: 7px;font-size: 17px;">Annual function</p>
      </div>

      <div class="mySlides">
        <img src="https://source.unsplash.com/collection/190727/1600x900" style="width: 98%;position: relative;left: 10px;top: 109px;">
        <p style="padding-bottom: 7px;font-size: 17px;">Annual function</p>
      </div>
      <a class="prev" id="prev1" onclick="plusSlides(-1)">&#10094;</a>
      <a class="next" onclick="plusSlides(1)">&#10095;</a>
    </div>
  </div>
</body>
</html>

内容的提问来源于stack exchange，提问作者Souvik