获取div中第一个跨度的背景色

<div id="container">
  <div>
    <span>Span 1</span>
  </div>
  <div>
    <span>Span 2</span>
  </div>
  <div>
    <span>Span 3</span>
  </div>
</div>

var firstDiv = document.getElementById("container").getElementsByTagName("div")[0];
var firstSpan = firstDiv.getElementsByTagName("span")[0];

var backgroundColor = window.getComputedStyle(firstSpan).backgroundColor;

console.log("第一个跨度的背景色是：" + backgroundColor);