js代码实现二级联动效果

<select id="sel" onchange="change()">
                
                <option value="0">运输方式</option>
                <option value="物流">物流</option>
                <option value="快递">快递</option>
                
            </select>
            
            <select id="son">
                <option value="0">物流</option>
                
            </select>

<script>
        var logistics=[
            ["德邦","华宇","申通","中邮"],
            ["圆通","韵达","天天","汇通"]
            
        ];
        function change(){
        var sle =document.getElementById('sel');
        var son =document.getElementById('son');
        
        var value=logistics[sle.selectedIndex-1];
        
        son.length=1;//清空物流框
        for(var i=0;i<value.length;i++){
        
            son[i+1]=new Option(value[i],value[i]);
                console.log(value[i]);
        }
        
        }
    
    </script>