JavaScript-事件【二级联动】

JavaScript - 事件 practice2

题目:

JavaScript-事件【二级联动】

<script type="text/javascript">
    window.onload = function(){
        //创建省份和城市数组,备用
        var provinceArr = ["湖南","湖北","广东"];
        var cityArr = ["长沙,株洲,湘潭,益阳,张家界",
            "武汉,宜昌,恩施,黄石","广州,东莞,惠州,深圳"];
        //通过ID获取select标签
        var selProvince = document.getElementById("province");
        var selCity = document.getElementById("city");
        //新建option标签,并添加进select标签中
        for(var i=0;i<provinceArr.length;i++) {
            var opP = document.createElement("option");
            opP.value = i;
            opP.innerHTML = provinceArr[i];
            selProvince.appendChild(opP);
        }
        //添加select标签的事件
        selProvince.onchange = function(){
            //刷新城市下拉列表
            selCity.options.length=1;
            //获取添加事件的select标签当前选择的项(option)的value
            var selIndex = this.value;
            if(selIndex>=0){
                //分割,城市数组
            var cityArrs = cityArr[selIndex].split(",");
                for(var j=0;j<cityArrs.length;j++){
                    var opC = document.createElement("option");
                    opC.value = cityArrs[j];
opC.innerHTML = cityArrs[j]; selCity.appendChild(opC); } } } }</script>

<body>
<h2>选择所在的省份及城市</h2>
省份:&nbsp;&nbsp;<select id="province">
    <option>-请选择省份-</option>
</select>
城市:&nbsp;&nbsp;<select id="city">
    <option>-请选择城市-</option>
</select>
</body>