三级联动菜单

三级联动考察的应该是对于数据的处理，只要清楚其中的关系，再多几级都是一样的：

html部分：

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>3级联动菜单</title>
    <script>
        var region = {
            广东:
            {
                "广州":["广州1","广州2","广州3"],

                "珠海":["珠海1","珠海2","珠海3"],

                "佛山":["佛山1"]
            },
            湖南:
            {
                "常德":["石门","桃源","临澧","汉寿"],

                "益阳":["益阳1","益阳2","益阳3"]
            }
        }
    </script>
</head>
    <body>

        <select id="province" onchange="change(this.value);">
            <option>请选择省份</option>
        </select>

        <select id="city" onchange="countyChange(this.value);">
            <option>请选择地市</option>
        </select>

        <select id="county">
            <option>请选择县城</option>
        </select>
    <script src='test.js'></script>
    </body>
</html>

js部分：

var province = document.querySelector("#province");
    var city = document.querySelector("#city");
    var county = document.querySelector("#county");
    //二级联动不用定义你选的省份,直接用省份(key)来决定下面的市(value)值
    var provinceName = null;

    for (ele in region){
        var op = new Option(ele , ele , false , false); //new Option("文本","值",true,true).后面两个true分别表示默认被选中和有效
        //console.log(op);
        province.options[province.length] = op;
    }

    var change = function(src){
        city.innerHTML = "";
        if(src === '请选择省份'){
            var op = new Option('请选择地市' , '请选择地市' , false , false);
            city.options[0] = op;
        }else{
            for (index in region[src]){
                //console.log(index);
                var op = new Option(index , index , false , false);
                city.options[city.length] = op;
            }
        }
        //记住选择省份的值
        provinceName=src;
        countyChange(city.value)
    }

    var countyChange = function(src2){
        county.innerHTML = "";
        if(src2 === '请选择地市'){
            var op = new Option('请选择县城','请选择县城', false , false);
            county.options[0] = op;
        }else{
            for (index in region[provinceName][src2]){
                //console.log(index);
                var op = new Option(region[provinceName][src2][index] , region[provinceName][src2][index] , false , false);
                county.options[county.length] = op;
            }
        }
    }

 

posted @ 2017-08-16 10:19  geewonii  阅读(651)  评论(0)  编辑  收藏  举报