html 实用的插件代码

以下是一些常用的 HTML 插件代码：

1. 点击展开/收起

<button onclick="myFunction()">展开/收起</button>

<div id="myDIV">
  <p>这是要展示的内容</p>
</div>

<script>
function myFunction() {
  var x = document.getElementById("myDIV");
  if (x.style.display === "none") {
    x.style.display = "block";
  } else {
    x.style.display = "none";
  }
}
</script>

2. 图片轮播

<div class="slideshow-container">

  <div class="mySlides fade">
    <img src="img1.jpg" style="width:100%">
  </div>

  <div class="mySlides fade">
    <img src="img2.jpg" style="width:100%">
  </div>

  <div class="mySlides fade">
    <img src="img3.jpg" style="width:100%">
  </div>

  <a class="prev" onclick="plusSlides(-1)">&#10094;</a>
  <a class="next" onclick="plusSlides(1)">&#10095;</a>

</div>

<script>
var slideIndex = 1;
showSlides(slideIndex);

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

function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  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";
}
</script>

3. 下拉菜单

<div class="dropdown">
  <button onclick="myFunction()" class="dropbtn">下拉菜单</button>
  <div id="myDropdown" class="dropdown-content">
    <a href="#">选项1</a>
    <a href="#">选项2</a>
    <a href="#">选项3</a>
  </div>
</div>

<script>
function myFunction() {
  document.getElementById("myDropdown").classList.toggle("show");
}

window.onclick = function(event) {
  if (!event.target.matches('.dropbtn')) {
    var dropdowns = document.getElementsByClassName("dropdown-content");
    var i;
    for (i = 0; i < dropdowns.length; i++) {
      var openDropdown = dropdowns[i];
      if (openDropdown.classList.contains('show')) {
        openDropdown.classList.remove('show');
      }
    }
  }
}
</script>

以上代码仅供参考，可以根据自己的需求进行修改和优化。