<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
<script>
var carsAndModels={};
carsAndModels['VO']=['V70','XC60','XC90'];
carsAndModels['VW']=['Golf','Polo','Scirocco','Touareg'];
carsAndModels['BMW']=['M6','X5','Z3'];
function ChangeCarList(selCar){
var modelList=document.getElementById("carmodel");
while (modelList.options.length){
modelList.remove(0);
}
var cars=carsAndModels[selCar];
if (cars){
for (var i=0;i<cars.length;i++){
var car=new Option(cars[i],i);
modelList.options.add(car);
}
}
}
</script>
</head>
<body onload="ChangeCarList();">
<select id="car" onchange="ChangeCarList(this.value);">
<option value="">-- Car --</option>
<option value="VO">Volvo</option>
<option value="VW">Volkswagen</option>
<option value="BMW">BMW</option>
</select>
<select id="carmodel"></select>
</body>
</html>
