延迟某个css背景图像的加载

window.addEventListener("load", function() {
  var style = document.createElement("style");
  style.innerHTML = ".background-image { background-image: url('path/to/your/image.jpg'); }";
  document.head.appendChild(style);
});

<link rel="stylesheet" href="path/to/your/stylesheet.css" media="print" />

window.addEventListener("load", function() {
  var link = document.querySelector('link[href="path/to/your/stylesheet.css"]');
  link.media = "all";
});