<view class="content">
  <view class="con">
    <block wx:for="{{50}}" wx:for-item="item" wx:for-index="__i0__">
      <view>滚动到底部</view>
    </block>
  </view>
  <view class="box">
    <input type="text" value="" placeholder="请输入" adjust-position="{{false}}"/>
  </view>
</view>
.content{
  width: 100%;
  height: 100%;
  overflow: hidden;
  overflow-y: auto;
}
.con{
  width: 100%;
}
.box{
  width: 200rpx;
  height: 200rpx;
  position: fixed;
  left: 0;
  top: 190rpx;
  background-color: #1653B5;
}