自己动手丰衣足食之三级联动

<!DOCTYPE html>
<html>

    <head>
        <meta charset="utf-8">
        <title></title>
    </head>

    <body>
        省:
        <select style="width: 100px;" id="pre" onchange="chg(this);">
            <option value="-1">请选择</option>
        </select>
        市:
        <select style="width: 100px;" id="city" onchange="chg2(this)" ;></select>
        区:
        <select style="width: 100px;" id="area"></select>
    </body>
    <script> //声明省 var pres = ["北京", "上海", "山东"]; //直接声明Array //声明市 var cities = [ ["东城", "昌平", "海淀"], ["浦东", "高区"], ["济南", "青岛"] ]; var areas = [ [ ["东城1", "东城2", "东城3"], ["昌平1", "昌平2", "昌平3"], ["海淀1", "海淀2", "海淀3"] ], [ ["浦东1", "浦东2", "浦东3"], ["高区1", "高区2", "高区3"] ], [ ["济南1", "济南2"], ["青岛1", "青岛2"] ] ] //设置一个省的公共下标 var pIndex = -1; var preEle = document.getElementById("pre"); var cityEle = document.getElementById("city"); var areaEle = document.getElementById("area"); //先设置省的值 for (var i = 0; i < pres.length; i++) { //声明option.<option value="pres[i]">Pres[i]</option> var op = new Option(pres[i], i); //添加 preEle.options.add(op); } function chg(obj) { if (obj.value == -1) { cityEle.options.length = 0; areaEle.options.length = 0; } //获取值 var val = obj.value; pIndex = obj.value; //获取ctiry var cs = cities[val]; //获取默认区 var as = areas[val][0]; //先清空市 cityEle.options.length = 0; areaEle.options.length = 0; for (var i = 0; i < cs.length; i++) { var op = new Option(cs[i], i); cityEle.options.add(op); } for (var i = 0; i < as.length; i++) { var op = new Option(as[i], i); areaEle.options.add(op); } } function chg2(obj) { var val = obj.selectedIndex; var as = areas[pIndex][val]; areaEle.options.length = 0; for (var i = 0; i < as.length; i++) { var op = new Option(as[i], i); areaEle.options.add(op); } } </script>

</html>

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