基于原生JavaScript实现城市二级联动下拉菜单

<html>
<head>
<title>Js城市二级联动选择插件</title>
<script>
var citys=new Array(
new Array("南京","淮安","扬州","常州",'其它'),
new Array("北京"),
new Array("天津"),
new Array("上海"),
new Array("其它")
);
function scity(pname,cname){
var province=['江苏省','北京','天津','上海','其它'];
document.write('<select id="pro" onchange="selectc(this)" name="'+pname+'">');
document.write('<option value="">--选择省份--</option>')
for(var i=0;i<province.length;i++){
 document.write('<option value="'+province[i]+'">'+province[i]+'</option>');
}
document.write('</select>');
document.write('<select id="city" name="'+cname+'">');
document.write('<option value="">--选择城市--</option>');
document.write('</select>');
selectc(document.getElementById("pro"));
}
function selectc(pobj){
  var index=pobj.selectedIndex-1;
   var cobj=document.getElementById("city");
   cobj.innerHTML='';
   if(index>=0){
   for(var i=0;i<citys[index].length;i++){
   var option=document.createElement("option");
   var text=citys[index][i];
   option.value=text;
   option.innerHTML=text;
   cobj.appendChild(option);
   }
   }else{
   var option=document.createElement("option");
   option.value="";
   option.innerHTML="--选择城市--";
   cobj.appendChild(option);
   }
}
</script>
</head>
<body>
<script>
 scity('p','c');
</script>
</body>
</html>