如何用JS判断div中内容为空，当为空时隐藏div

<div id="content"></div>
<input type="button" id="btn" value="点击">
 
var content = document.getElementById("content");
    var btn = document.getElementById("btn");
    btn.onclick = function(){
      if(content.innerText == ''){
        content.style.display = 'none'
      }
 }

content.innerText == ''