SOURCE

document.getElementById("begin").addEventListener("click", function(){
var h1 = element1.clientHeight;
element1.style.height = (h1 * 2) + 'px';

var h2 = element2.clientHeight; 
element2.style.height = (h2 * 2) + 'px';

var h3 = element3.clientHeight;
element3.style.height = (h3 * 2) + 'px';
})

<div id="begin">开始</div>

<div id="element1"></div>
<div id="element2"></div>
<div id="element3"></div>

#element1,#element2,#element3{
  width:50px;
  height:50px;
  background-color:red;
  margin:100px;
}