前端：
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Document</title></head><body> ???<img src="" id=‘myimg‘ width="50" height="50"> ???<script type="text/javascript"> ???????????????//先让浏览器加载img标签，然后在JS中为img标签指定图片 ????????document.getElementById("myimg").src="vichin.jpg"; ???</script></body></html><!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>Document</title></head><body> ???<div>添加图片缓存</div> ???<img src="vichin.jpg" id="img2" width="100" height="100"> ???<script type="text/javascript"> ???????????????window.onload=function () { ????????????var myimgs=new Image(); ????????????myimgs.src="vichin.jpg" ????????????myimgs.onload=function () { ?????????????????alert(‘hi、vichin!‘); ????????????} ???????????????????}//这样图片只会在页面初次请求时被加载 ???</script></body></html>asp.net网站性能优化
原文地址：https://www.cnblogs.com/vichin/p/9785838.html