怎么JS实现多重选择?

[weijianyu2000]

function SelectArea(obj){
var index = obj.selectedIndex;
var areano ="";
var areaname = "";
var k=0;
areano = obj.options[index].value;
areaname = obj.options[index].text;
document.getElementById('schoId').options.length=0;
document.getElementById('schoId').options[k] = new Option;
document.getElementById('schoId').options[k].value=areano;
document.getElementById('schoId').options[k].text=areaname+"教育局";

document.getElementById('userId1').options.length=0;
document.getElementById('userId2').options.length=0;
<%
if (list_scho !=null){
for(int i = 0;i<list_scho.size();i++){
hm = (HashMap)list_scho.get(i);
%>
if (areano=='<%= hm.get("scho_areano").toString().trim()%>'){
eval("document.getElementById('schoId').options[k+1] = new Option");
document.getElementById('schoId').options[k+1].value= "<%= hm.get("scho_code").toString().trim()%>";
document.getElementById('schoId').options[k+1].text = "[<%= hm.get("scho_code").toString().trim()%>]<%= hm.get("scho_name").toString().trim()%>";
k++;
}
<%}
}%>
}
这个原来是单选的,我现在要改成多选的,要怎么改啊?本来把index改成index=obj.getSelectIndex;
下边怎么改都不行.急求救啊!

[weijianyu2000]

nobody!!!

[ctbu5019]

试试用Switch case语句来调试调试~~我没仔细看你代码，不过我觉得可以试试这个方法