给IMG添加属性

<script>
window.onload=function(){
var imgs=document.getElementsByTagName('img');

for(var i=0;i<imgs.length;i++){
imgs[i].setAttribute('data-src','https://www.qixibang.cc/wp-content/themes/TangStyle-master/images/loading.gif');
imgs[i].setAttribute('class','scrollLoading');
document.getElementsByTagName('img')[0].className = 'scrollLoading'; //设置为新的
document.getElementsByTagName('img')[0].className += ' scrollLoading'; //在原来的后面加这个
// document.getElementsByTagName('img')[0].classList.add("snow-container"); //与第一个等价
}
}

</script>