源码分享：HTML+CSS动画打造个性化登录页！

<div id="particles-js">
    <div class="login">
      <div class="login-top">
        登录
      </div>
      <div class="login-center clearfix">
        <div class="login-center-img"><img src="img/name.png"/></div>
        <div class="login-center-input">
          <input type="text" name="" value="" placeholder="请输入您的用户名" onfocus="this.placeholder=''" onblur="this.placeholder='请输入您的用户名'"/>
          <div class="login-center-input-text">用户名</div>
        </div>
      </div>
      <div class="login-center clearfix">
        <div class="login-center-img"><img src="img/password.png"/></div>
        <div class="login-center-input">
          <input type="password" name=""value="" placeholder="请输入您的密码" onfocus="this.placeholder=''" onblur="this.placeholder='请输入您的密码'"/>
          <div class="login-center-input-text">密码</div>
        </div>
      </div>
      <div class="login-button">
        登陆
      </div>
    </div>
    <div class="sk-rotating-plane"></div>
</div>

function hasClass(elem, cls) {
    cls = cls || '';
    if (cls.replace(/\s/g, '').length == 0) return false; //当cls没有参数时，返回false
    return new RegExp(' ' + cls + ' ').test(' ' + elem.className + ' ');
  }
   
  function addClass(ele, cls) {
    if (!hasClass(ele, cls)) {
      ele.className = ele.className == '' ? cls : ele.className + ' ' + cls;
    }
  }
   
  function removeClass(ele, cls) {
    if (hasClass(ele, cls)) {
      var newClass = ' ' + ele.className.replace(/[\t\r\n]/g, '') + ' ';
      while (newClass.indexOf(' ' + cls + ' ') >= 0) {
        newClass = newClass.replace(' ' + cls + ' ', ' ');
      }
      ele.className = newClass.replace(/^\s+|\s+$/g, '');
    }
  }
    document.querySelector(".login-button").onclick = function(){
        addClass(document.querySelector(".login"), "active")
        setTimeout(function(){
          addClass(document.querySelector(".sk-rotating-plane"), "active")
          document.querySelector(".login").style.display = "none"
        },800)
        setTimeout(function(){
          removeClass(document.querySelector(".login"), "active")
          removeClass(document.querySelector(".sk-rotating-plane"), "active")
          document.querySelector(".login").style.display = "block"
          alert("登录成功")
          
        },5000)
    }