在javascript中有一个 load 事件侦听器，您的最佳选择可能是为每个“img”元素设置一个事件侦听器，以删除回退，

document.querySelectorAll('.loaded-img').forEach(elm => {
   elm.addEventListener('load', (event) => {
      event.target.previousElementSibling.remove() // This is generally bad practice IMO, 
      //here I'm assuming the fallback img is right before the actual img but for 
      //consistency may want to do something like 
      //event.target.parentElement.querySelector('.fallback-img').remove()
      //Could also just add a forwards animation to opacity 1 -> 1;
   }, { once:true }) // Only runs once per Image.
})

或者可以像这样向父级添加事件侦听器，

document.querySelector('.img-parent').addEventListener('load', (event) => {
   if (event.target.classList == 'image-class') // ... Same as above
})