SOURCE

const obj = {}
Object.defineProperty(obj,'text',{
  get:()=>{
    console.log('正在获取数据')
  },
  set:(newValue)=>{
    console.log('设置为：'+newValue)
    document.getElementById('input').value = newValue;
    document.getElementById('span').innerHTML = newValue 
  }
})

<main>
	<p>请输入</p>
	<input id='input' type='text'/>
<p id='span'></p>
</main>