JS _ advertisement code for displaying images without images at the specified position

With the help of a friend, the thumbnail is displayed after the thumbnail is saved. if not, the automatically loaded ad code is displayed. because shtml is used. I directly used include in the page to load the advertisement. If you are interested in shtml. see: html
It is also the same code to introduce js. Replace img_failed.innerHTML = with the JS you call (not tested );
In addition, it is worth noting that img_failed.innerHTML = will directly display html. If your html contains "(double quotation marks), please change it to" (single quotation marks ), or directly do not add. otherwise there will be problems.
The following two links can be compared for details:

The Code is as follows: