html部分

                  <select name="level1">
                        <option>无设置商品分类,请先去设置</option>
                    </select>

                    <select name="level2">

                    </select>

                    <select name="level3">
                        <option value=""></option>
                    </select>

script部分

<!--分类联动代码-->
<script>
    var classifys = [{"id":"1","pid":"0","name":"\u96f6\u98df1","level":"1"},{"id":"2","pid":"1","name":"\u996e\u6599","level":"2"},{"id":"3","pid":"2","name":"\u53ef\u53e3\u53ef\u4e50","level":"3"},{"id":"4","pid":"2","name":"\u96ea\u78a7","level":"3"},{"id":"5","pid":"0","name":"\u73a9\u5177","level":"1"},{"id":"14","pid":"5","name":"\u5927\u73a9\u5177","level":"2"},{"id":"7","pid":"5","name":"\u5c0f\u73a9\u5177","level":"2"},{"id":"8","pid":"2","name":"\u67c3\u6aac\u6c34","level":"3"},{"id":"9","pid":"1","name":"\u5c0f\u5403","level":"2"},{"id":"10","pid":"9","name":"\u5305\u5b50","level":"3"},{"id":"11","pid":"1","name":"\u4fdd\u5065","level":"2"},{"id":"12","pid":"11","name":"\u7ef4\u751f\u7d20C","level":"3"}];
    //渲染分类
    function reviewClassify(level,id){
        var html = '';
        var ischange = false;
        var nextid = '';
        $(classifys).each(function(index,value){

            if(level==1 && value.level==1){
                html +='<option value='+value.id+">"+value.name+"</option>";
                if(nextid==''){
                    ischange = true;
                    nextid = value.id;
                }
            }else if(level!=1){
                if(id == value.pid){
                    if(!ischange){
                        ischange = true;
                        nextid = value.id;
                    }
                    html +='<option value='+value.id+">"+value.name+"</option>";
                }
            }

        });

        $("select[name='level"+level+"']").html(html);
        level += 1;
        if(level>3){return;}
        reviewClassify(level,nextid);
    }

    $("select").change(function(){
        var id = $(this).val();
        var level = parseInt($(this).attr("name").substring(5)); //截取当前level出来
        reviewClassify(level+1,id);
    });

    reviewClassify(1,'');//初始化分类
</script>