اینطوری!
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<HTML>
<HEAD>
<TITLE>Test</TITLE>
</HEAD>
<script language="javascript">
function checkIt(){
if(document.all.main.item(document.all.mai n.selectedIndex).value==1)
a();
else
b();
}
function b(){
clearAll("first");
var oOption = document.createElement("OPTION");
oOption.text="BMW";
oOption.value="5";
document.all.first.add(oOption);
oOption = document.createElement("OPTION");
oOption.text="Benz";
oOption.value="6";
document.all.first.add(oOption);
oOption = document.createElement("OPTION");
oOption.text="Pride";
oOption.value="6";
document.all.first.add(oOption);
}
function a(){
clearAll("first");
var oOption = document.createElement("OPTION");
oOption.text="Apples";
oOption.value="5";
document.all.first.add(oOption);
oOption = document.createElement("OPTION");
oOption.text="Orange";
oOption.value="6";
document.all.first.add(oOption);
}
function clearAll(selid){
while(document.all.item(selid).length> 0)
document.all.item(selid).remove(0) ;
}
</script>
<STYLE>
a{font-family:tahoma;font-size:12px;color:blue;}
</style>
<BODY>
<a href="javascript:a()">This is a test</a>
<SELECT id="main" onchange="checkIt()">
<OPTION value="1">Fruite
<OPTION value="2">Car
</SELECT>
<SELECT id="first">
<OPTION value="1">Apple
<OPTION value="2">Orange
</SELECT>
</BODY>
</HTML>