IE兼容性问题，目前已兼容到IE9

jodconverter-web/src/main/resources/static/js/lazyload.js

 function isInSight(el) {
-  const bound = el.getBoundingClientRect();
-  const clientHeight = window.innerHeight;
-  //只考虑向下滚动加载
-  //const clientWidth=window.innerWeight;
-  return bound.top <= clientHeight + 100;
+    var bound = el.getBoundingClientRect();
+    var clientHeight = window.innerHeight;
+    //只考虑向下滚动加载
+    //const clientWidth=window.innerWeight;
+    return bound.top <= clientHeight + 100;
 }
 
-let index = 0;
+var index = 0;
+
 function checkImgs() {
-  const imgs = document.querySelectorAll('.my-photo');
-  for (let i = index; i < imgs.length; i++) {
-    if (isInSight(imgs[i])) {
-      loadImg(imgs[i]);
-      index = i;
+    var imgs = document.querySelectorAll('.my-photo');
+    for (var i = index; i < imgs.length; i++) {
+        if (isInSight(imgs[i])) {
+            loadImg(imgs[i]);
+            index = i;
+        }
     }
-  }
 }
 
 function loadImg(el) {
-  const source = el.dataset.src;
-  el.src = source;
+    var source = el.getAttribute("data-src");
+    el.src = source;
 }
+// var mustRun = 500
+// function throttle(fn, mustRun) {
+//     var timer = null;
+//     var previous = null;
+//     return function() {
+//         var now = new Date();
+//         var context = this;
+//         var args = arguments;
+//         if (!previous) {
+//             previous = now;
+//         }
+//         var remaining = now - previous;
+//         if (mustRun && remaining >= mustRun) {
+//             fn.apply(context, args);
+//             previous = now;
+//         }
+//     }
+// }
+
 
-function throttle(fn, mustRun = 500) {
-  const timer = null;
-  let previous = null;
-  return function() {
-    const now = new Date();
-    const context = this;
-    const args = arguments;
-    if (!previous) {
-      previous = now;
+function throttle(fn) {
+    var timer = null;
+    var previous = null;
+    return function () {
+        var now = new Date();
+        var context = this;
+        var args = arguments;
+        if (!previous) {
+            previous = now;
+        }
+        var remaining = now - previous;
+        setTimeout(refresh(fn, remaining, context, args, previous, now));
     }
-    const remaining = now - previous;
-    if (mustRun && remaining >= mustRun) {
-      fn.apply(context, args);
-      previous = now;
+}
+
+function refresh(fn, remaining, context, args, previous, now) {
+    if (remaining >= 500) {
+        fn.apply(context, args);
+        previous = now;
     }
-  }
 }