<ul class="todo-content">     
      <li class="todo-ltem">
        <div class="todo-tip">
          <p>fhasjfas</p>
        </div>
        <div class="todo-btnlist">
          <button class="btn-finish">完成</button>
          <button class="btn-finish">修改</button>
          <button class="btn-finish">删除</button>
        </div>
      </li>
      <li class="todo-ltem">
        <div class="todo-tip">
          <p>fhasjfas</p>
        </div>
        <div class="todo-btnlist">
          <button class="btn-finish">完成</button>
          <button class="btn-finish">修改</button>
          <button class="btn-finish">删除</button>
        </div>
<li class="todo-ltem">
        <div class="todo-tip">
          <p>你好</p>
        </div>
        <div class="todo-btnlist">
          <button class="btn-finish">完成</button>
          <button class="btn-finish">修改</button>
          <button class="btn-finish">删除</button>
        </div>
<li class="todo-ltem">
        <div class="todo-tip">
          <p>你好啊</p>
        </div>
        <div class="todo-btnlist">
          <button class="btn-finish">完成</button>
          <button class="btn-finish">修改</button>
          <button class="btn-finish">删除</button>
        </div>
      </li>
    </ul>

 $('#findinput').keydown(function(event){
    if(event.keyCode == 13){
      var keyword = $(this).val()
      // alert(keyword)
      $('li').hide()//将原有的内容隐藏
      //然后将含有keyword的li进行渐变显示
      $("p").filter(":Contains("+keyword+")").parents('.todo-ltem').fadeIn(2000)
    }
  })