Create a simple loop insertion effect based on insertBefore_javascript skills

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【Function Description】

Use insertBefore to create a simple loop insertion effect

[HTML code description]

<ul class="list" id="list">
 <li class="in">1</li>
 <li class="in">2</li>
 <li class="in">3</li>
 <li class="in">4</li>
 <li class="in">5</li>
 <li class="in">6</li>  
</ul>

[CSS code description]

.in{
 height: 20px;
 line-height: 20px;
 width: 20px;
 background-color: blue;
 text-align: center;
 color: white;
}

[JS code description]

var oList = document.getElementById('list');
//新增一个li元素
var oAdd = document.createElement('li');
//设置新增元素的css样式
oAdd.className = "in";
oAdd.style.cssText = 'background-color:red;border-radius:50%';
//添加到oList中
oList.insertBefore(oAdd,null);
var num = -1;
var max = oList.children.length;
function incrementNumber(){
 num++;
 //oList.getElementsByTagName('li')[max]相当于null，所以不报错
 oList.insertBefore(oAdd,oList.getElementsByTagName('li')[num]); 
 if(num == max){
  num = -1;
 } 
 if(num == 0){
  num = 1;
 }
 setTimeout(incrementNumber,1000);
}
setTimeout(incrementNumber,1000);

Okay, the above is the entire content of this article. The code is very simple. I believe everyone can understand it. Friends who need it can refer to this article. I hope you like it.