新手，哪位大哥帮帮！

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title></title>
<script language="Javascript" type="text/javascript">
<!--
    var city=[
    ["南京","苏州","南通","常州"],
    ["福州","福安","龙岩","南平"],
    ["广州","潮阳","潮州","澄海"]
];function getCity(){
    var sltProvince=document.forms["theForm"].elements["province"];
    var sltCity=document.forms["theForm"].elements["city"];
    var provinceCity=city[sltProvince.selectedIndex-1];    sltCity.length=1;
    for(var i=0;i<provinceCity.length;i++){
        sltCity[i+1]=new Option(provinceCity[i],provinceCity[i]);
    }
}
//-->
</script>
</head><body>
<form name="theForm">
<select name="province" onchange="getCity()">
       <option value="0">请选择所在省份</option>
       <option value="江苏省">江苏省</option>
       <option value="福建省">福建省</option>
       <option value="广东省">广东省</option>
</select>
<select name="city">
       <option value="0">请选择所在城市</option>
</select>
</form>
</body>
<html>吃饭免了，给分吧，穷死了