JS下拉框之間的聯動(兩級)
阿新 • • 發佈：2019-02-08
<html>
<meta charset="utf-8"><body>
<select id="first" onChange="change()">
<option selected="selected">湖北</option>
<option>廣東</option>
</select>
<select id="second">
<option>黃岡</option>
<option selected="selected">武漢</option>
</select>
<script>
function change()
{
var x = document.getElementById("first");
var y = document.getElementById("second");
y.options.length = 0; // 清除second下拉框的所有內容
if(x.selectedIndex == 0)
{
y.options.add(new Option("黃岡", "0"));
y.options.add(new Option("武漢", "1", false, true)); // 預設選中省會城市
}
if(x.selectedIndex == 1)
{
y.options.add(new Option("深圳", "0"));
y.options.add(new Option("廣州", "1", false, true)); // 預設選中省會城市
y.options.add(new Option("肇慶", "2"));
}
}
</script>
</body>
</html>