帮我写一个模态框，手机端的，展示身份证照片

好的，以下是一个简单的模态框代码，用于展示身份证照片：

<!-- HTML代码 -->
<div id="myModal" class="modal">
  <span class="close">&times;</span>
  <img class="modal-content" id="idCardImg">
  <div id="caption"></div>
</div>


<!-- CSS代码 -->
<style>
/* Modal */
.modal {
  display: none; /* Hidden by default */
  position: fixed; /* Stay in place */
  z-index: 1; /* Sit on top */
  padding-top: 20px; /* Location of the box */
  left: 0;
  top: 0;
  width: 100%; /* Full width */
  height: 100%; /* Full height */
  overflow: auto; /* Enable scroll if needed */
  background-color: rgb(0,0,0); /* Fallback color */
  background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
}

/* Modal Content (image) */
.modal-content {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
}

/* Caption of Modal Image */
#caption {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
  text-align: center;
  color: #ccc;
  padding: 10px 0;
  height: 150px;
}

/* Add Animation */
.modal-content, #caption {
  animation-name: zoom;
  animation-duration: 0.6s;
}

@keyframes zoom {
  from {transform:scale(0)}
  to {transform:scale(1)}
}

/* The Close Button */
.close {
  position: absolute;
  top: 15px;
  right: 35px;
  color: #f1f1f1;
  font-size: 40px;
  font-weight: bold;
  transition: 0.3s;
}

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

/* Responsive Columns */
@media screen and (max-width: 700px) {
  .modal-content {
    width: 100%;
  }
}
</style>


<!-- JavaScript代码 -->
<script>
// 获取模态框元素
var modal = document.getElementById("myModal");

// 获取图片元素并将其放入模态框中
var img = document.getElementById("idCardImg");
var modalImg = document.getElementsByClassName("modal-content")[0];
var captionText = document.getElementById("caption");
img.onclick = function(){
  modal.style.display = "block";
  modalImg.src = this.src;
  captionText.innerHTML = this.alt;
}

// 获取关闭按钮元素并绑定关闭模态框事件
var span = document.getElementsByClassName("close")[0];
span.onclick = function() { 
  modal.style.display = "none";
}
</script>

使用时，只需将身份证照片的路径及其描述添加到img的src和alt属性中即可。