JavaScript淘宝相册切换

  <img src="images/c1.jpg" id="bigImg">
  <ul>
    <li class="active">
      <a href="JavaScript::">
        <img src="images/c1.jpg" alt="" class="smallImg">
      </a>
    </li>
    <li>
      <a href="JavaScript::">
        <img src="images/c2.jpg" alt="" class="smallImg">
      </a>
    </li>
    <li>
      <a href="JavaScript::">
        <img src="images/c3.jpg" alt="" class="smallImg">
      </a>
    </li>
    <li>
      <a href="JavaScript::">
        <img src="images/c4.jpg" alt="" class="smallImg">
      </a>
    </li>
  </ul>

    var bigImg = document.getElementById('bigImg');
    var smallImg = document.getElementsByClassName('smallImg');

    for (var i = 0; i < smallImg.length; i++) {
    
    
      smallImg[i].onmouseover = function () {
    
    
        for (var j = 0; j < smallImg.length; j++) {
    
    
          smallImg[j].parentNode.parentNode.setAttribute('class', '')
        }
        var smallImgSrc=this.getAttribute('src');
        bigImg.setAttribute('src',smallImgSrc)
        this.parentNode.parentNode.setAttribute('class', 'active')
      }
    }

效果