console 命令行工具 X clear

console

window.onload = function() {
  var ele = document.getElementById('rect')
  var big = document.getElementById('big')
  big.onclick=function() {
      console.log(ele.getBoundingClientRect().left)
  		console.log(ele.getBoundingClientRect().right)
  }
}

<div id="rect"></div>
<div id='big'>查看结果</div>

#rect {
  width: 200px;
  height: 200px;
  background: orange;
}

#big {
  width: 120%;
  background: pink;
}