fix: PDF/word图片模式预览时, 下翻图片时频繁请求图片资源

server/src/main/resources/static/js/lazyload.js

@@ -19,8 +19,12 @@ function checkImgs() {
 }
 
 function loadImg(el) {
+    var loaded = el.getAttribute("loaded");
+    if (!Boolean(loaded)) {
         var source = el.getAttribute("data-src");
+        el.setAttribute("loaded", true);
         el.src = source;
+    }
 }
 // var mustRun = 500
 // function throttle(fn, mustRun) {