console
var scrollHeight = document.getElementById("a").scrollHeight;
console.log('scrollHeight',scrollHeight);
var scrollTop = document.getElementById("a").scrollTop;
console.log('scrollTop',scrollTop);
function a(){
let scrollTop = document.getElementById("a").scrollTop;
if(scrollTop>0){
console.log('xiaoshi')
}
}
var clientHeight = document.getElementById("a").clientHeight;
console.log('clientHeight',clientHeight);
a();
<div id="a">
<ul>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
<li>啊打发手动阀撒旦</li>
</ul>
</div>
#a{
height:100px;
overflow:auto;
}