不多bb，上硬货

html代码

js代码：
var province = document.querySelector(‘#province‘); //省
var cityNode = document.querySelector(‘#city‘); //市
var areaNode = document.querySelector(‘#area‘); //区

    // bind 绑定  Province 省份
    function bindProvince() {
        // option  选项  定义下拉(select)列表中的一个选项（一个条目）
        var options = ‘<option value="-1">请选择...</option>‘;
        // forEach() 遍历
        city_code.forEach(function(c) {
            options += `<option value="${c.code}">${c.name}</option>`;
        })
        province.innerHTML = options
    }

    bindProvince();


    // bind 绑定  City  市
    // code 编码
    function bindCity(provinceCode) {
        var qq = function(v) {
                return v.code === provinceCode;
            }
            // filter() 过滤
        var provinceArr = city_code.filter(qq);
        var city = [];
        if (provinceArr.length > 0) {
            var province = provinceArr[0]
            city = province.city;
        }

        var options = ‘<option value="-1">请选择...</option>‘;
        var ww = function(c) {
            options += `<option value="${c.code}">${c.name}</option>`;
        }
        city.forEach(ww);

        cityNode.innerHTML = options;
    }

    bindCity("-1");

    //绑定 区
    function bindArea(provinceCode, cityCode) {
        var provinceArr = city_code.filter(function(v) {
            return v.code === provinceCode;
        });
        var area = [];
        if (provinceArr.length > 0) {
            var province = provinceArr[0]
            var cityArr = province.city;
            var oneCityArr = cityArr.filter(function(c) {
                return c.code === cityCode;
            });
            if (oneCityArr.length > 0) {
                var city = oneCityArr[0];
                area = city.area;
            }
        }

        var options = ‘<option value="-1">请选择...</option>‘;
        area.forEach(function(c) {
            options += `<option value="${c.code}">${c.name}</option>`;
        })

        areaNode.innerHTML = options;
    }

    bindArea("-1", "-1")

    province.addEventListener(‘change‘, function(e) {
        bindCity(e.target.value);
        bindArea(e.target.value, "-1")
    })

    cityNode.addEventListener(‘change‘, function(e) {
        var provinceCode = province.value;
        var cityCode = e.target.value;
        bindArea(provinceCode, cityCode)
    })

因为这里需要城市数据，所以我把数据传到码云上了，有需要的小伙伴可以自己去看
链接：https://gitee.com/s272/blog-garden.git

前端常见编程题（四）：三级联动