使用链接在javascript中显示更多文本

<p id="text">这是一段文本内容。... <a href="#" id="link">显示更多</a></p>

var link = document.getElementById("link");
var text = document.getElementById("text");
var isExpanded = false;

link.addEventListener("click", function(e) {
  e.preventDefault();
  
  if (isExpanded) {
    text.style.height = "1.5em";
    link.innerHTML = "显示更多";
  } else {
    text.style.height = "auto";
    link.innerHTML = "收起";
  }
  
  isExpanded = !isExpanded;
});

<p>这是一段文本内容。... <a href="#" id="link">显示更多</a></p>

<div id="modal" class="modal">
  <div class="modal-content">
    <span id="close" class="close">&times;</span>
    <p>更多文本内容...</p>
  </div>
</div>

.modal {
  display: none;
  position: fixed;
  z-index: 1;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgb(0,0,0);
  background-color: rgba(0,0,0,0.4);
}

.modal-content {
  background-color: #fefefe;
  margin: 15% auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
}

.close {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

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

var link = document.getElementById("link");
var modal = document.getElementById("modal");
var close = document.getElementById("close");

link.addEventListener("click", function(e) {
  e.preventDefault();
  modal.style.display = "block";
});

close.addEventListener("click", function() {
  modal.style.display = "none";
});