用js写三级联动

<!DOCTYPE html>
<html lang="en">
 
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
    body {
        background: #242424;
        color: green;
        font-size: 20px;
    }
    </style>
</head>
 
<body>
    <select id="province" size="1" onchange="change(this.value);">
        <option>请选择省份</option>
    </select>
    <select id="city" size="1" onchange="countyChange(this.value);">
        <option>请选择地市</option>
    </select>
    <select id="county" size="1">
        <option>请选择县城</option>
    </select>
    <script type="text/javascript">
    var region = {
        湖南:
 
        {
 
            "常德": ["石门", "桃源", "临澧", "汉寿"],
 
            "益阳": ["益阳1", "益阳2", "益阳3"],
 
            "岳阳": ["岳阳1", "岳阳2", "岳阳3", "岳阳4", "岳阳5", "岳阳6", "岳阳7"],
 
            "永州": ["永州1", "永州2"],
 
            "郴州": ["郴州1", "郴州2", "郴州3"],
 
            "湘潭": ["湘潭1", "湘潭2", "湘潭3"]
 
        },
 
        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"]
 
        }
 
    }
 
    var province = document.getElementById("province");
    var city = document.getElementById("city");
    var county = document.getElementById("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 (var ele in region) {
        // text:字符串，指定option对象的text属性(即<option></option>之间的文字)
        // value:字符串，指定option对象的value属性
        // defaultSelected:布尔值，指定option对象的defaultSelected属性
        // selected:布尔值，指定option对象的selected属性
        var op = new Option(ele, ele, false, false);
        province.options[province.length] = op;
 
    }
 
    var change = function(src)
 
    {
        city.innerHTML = "";
        for (index in region[src]) {
            var op = new Option(index, index, false, false);
            city.options[city.length] = op;
        }
 
        //记住你选的省份的值是什么
        provinceName = src;
 
    }
 
    var countyChange = function(src2)
 
    {
        county.innerHTML = "";
        //关键是如何表示:第三级县城的数据:??
        for (index in region[provinceName][src2]) {
            //alert(index);
            var op = new Option(region[provinceName][src2][index], region[provinceName][src2][index], false, false);
            county.options[county.length] = op;
        }
 
    }
    </script>
    <script src="http://libs.baidu.com/jquery/1.9.1/jquery.min.js"></script>
    <script>
    $(function() {
        $('button').click(function(argument) {
            $('#box').toggle(500);
        });
    });
    </script>
    <script>
    var Things = document.getElementsByTagName('*');
    for (var i = 0; i < Things.length; i++) {
        Things[i].style.backgroundColor = '#242424';
        Things[i].style.color = '#A57800';
    }
    </script>
</body>
 
</html>
用js写三级联动

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