JS练习之二级联动

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<select id="provinces">
    <option value="">请选择省份</option>
    <!--<option value="">河北省</option>-->
    <!--<option value="">河南省</option>-->
    <!--<option value="">北京</option>-->
</select>

<select name="" id="citys">
    <option value="">请选择城市</option>
</select>



<script>

//    a={name:"alex"};
//    b={"name":"alex"};
//    console.log(a.name);
//    console.log(b["name"]);

//      data={"河北省":["石家庄","廊坊"],"山西":["晋城","大同"],"陕西":["西安","延安"]};
//    console.log(data);
//    console.log(typeof data);
//    console.log(data["河北省"]);
//    console.log(data.河北省);
//
//      for (var i in data){
//          console.log(i);
//      }


    data={"河北省":["石家庄","廊坊"],"山西":["晋城","大同"],"陕西":["西安","延安"]};
    var pro_ele=document.getElementById("provinces");
    var city_ele=document.getElementById("citys")

    for(var i in data){
        var ele=document.createElement("option");
        ele.innerHTML=i;
        pro_ele.appendChild(ele)
    }

    pro_ele.onchange=function () {
        console.log(this.selectedIndex);
        console.log(this.options[this.selectedIndex])

        var citys=data[this.options[this.selectedIndex].innerHTML];

        city_ele.options.length=1;

        for(var i=0;i<citys.length;i++){
            var ele=document.createElement("option");
             ele.innerHTML=citys[i];
            city_ele.appendChild(ele)
        }

    }



</script>


</body>
</html>
View Code
JS练习之二级联动

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