使用jQuery预加载图像

$.preload(["image1.jpg", "image2.jpg"], {
  onComplete: function() {
    // 所有图像都已预加载
  },
  onProgress: function(percent) {
    // 预加载进度
  }
});

var images = ["image1.jpg", "image2.jpg"];
var loaded = 0;

$.each(images, function(index, image) {
  $("<img>")
    .attr("src", image)
    .on("load", function() {
      loaded++;
      if (loaded === images.length) {
        // 所有图像都已预加载
      }
    });
});

function preloadImages(images) {
  return Promise.all(
    images.map(
      image =>
        new Promise(resolve => {
          const img = new Image();
          img.src = image;
          img.onload = () => resolve(img);
        })
    )
  );
}

preloadImages(["image1.jpg", "image2.jpg"]).then(() => {
  // 所有图像都已预加载
});