连动下拉菜单—HTMLCSS教程

<html>
<head>
<title>List</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script LANGUAGE="javascript">
<!--
var onecount;
onecount=0;

subcat = new Array();
subcat[0] = new Array("徐汇区","01","001");
subcat[1] = new Array("嘉定区","01","002");
subcat[2] = new Array("黄浦区","01","003");
subcat[3] = new Array("南昌市","02","004");
subcat[4] = new Array("九江市","02","005");
subcat[5] = new Array("上饶市","02","006");

onecount=6;

function changelocation(locationid)
{
document.myform.smalllocation.length = 0;

    var locationid=locationid;
    var i;
    document.myform.smalllocation.options[0] = new Option('====所有地区====','');
    for (i=0;i < onecount; i++)
        {
            if (subcat[i][1] == locationid)
            {
            document.myform.smalllocation.options[document.myform.smalllocation.length] = new Option(subcat[i][0], subcat[i][2]);
            }
        }

    }

//-->
</script>
</head>
<body>
<form name="myform" method="post">
    <select name="biglocation" onChange="changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value)">
        <option value="01" selected>上海</option>
        <option value="02">江西</option>
    </select>
    <select name="smalllocation">
        <option selected value="">==所有地区==</option>
    </select>
</form>
<script LANGUAGE="javascript">
<!--
    changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value);

//-->
</script>
</body>
</html>