Eksempelvis:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"
http://www.w3.org/TR/html4/loose.dtd"><html>
<head>
<title>Skift flere selects</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">
html,body{height:100%;margin:0px;border:0px;padding:0px;font-family:tahoma,verdana,arial,sans-serif;font-size:small;}
</style>
<script language="javascript" type="text/javascript">
var sp = [];
sp[sp.length] = [ ["1024 kbit/s","2048 kbit/s","4096 kbit/s"], ["256 kbit/s","512 kbit/s","1024 kbit/s"] ];
sp[sp.length] = [ ["512 kbit/s","1024 kbit/s"], ["128 kbit/s","256 kbit/s","512 kbit/s"] ];
function showSpeeds(elm){
var sels = [elm.form.download, elm.form.upload];
if(elm.selectedIndex==0){
sels[0].length = 1;
sels[1].length = 1;
}else{
var arrNum = elm.selectedIndex-1;
for(i=0;2>i;i++){
sels[i].length = 1;
for(j=0,jm=sp[arrNum][i].length;jm>j;j++){
sels[i].options[sels[i].length] = new Option(sp[arrNum][i][j],j);//det sidste ,j giver en value på optionen
//denne value kan måske undværes, hvis du bare skal bruge værdien direkte
}
}
}
}
</script>
</head>
<body>
<form id="minForm" name="minForm">
Vælg selskab:<br>
<select name="selskab" id="selskab" onchange="showSpeeds(this);">
<option value="">-- Vælg her --<br>
<option value="1">TDC<br>
<option value="2">Telia<br>
</select>
<br>Vælg downloadhastighed:<br>
<select name="download" id="download">
<option value="">-- Vælg her --<br>
</select>
<br>Vælg uploadhastighed:<br>
<select name="upload" id="upload">
<option value="">-- Vælg her --<br>
</select>
<br>
<input type="submit" value="send">
</form>
</body>
</html>