完全符合你的要求~~并可以跳焦点~~<form name="form1">
<SELECT id=select1 size=12>
<OPTION>111111111111111111</OPTION>
<OPTION>222222222222222222</OPTION>
<OPTION>333333333333333333</OPTION>
<OPTION>444444444444444444</OPTION>
</SELECT>
<input type="button" value="add" onclick="addOption(select1)"><br/>
</form><script language="javascript">
sName="select";
var nTotal = 0;
function addOption(obj)
{
var ss = document.createElement("option");
nTotal++;
ss.value = sName + nTotal;
ss.text= sName + nTotal;
obj.add(ss);
ss.selected=true;
}
</script>
<SELECT id=select1 size=12>
<OPTION>111111111111111111</OPTION>
<OPTION>222222222222222222</OPTION>
<OPTION>333333333333333333</OPTION>
<OPTION>444444444444444444</OPTION>
</SELECT>
<input type="button" value="add" onclick="addOption(select1)"><br/>
</form><script language="javascript">
sName="select";
var nTotal = 0;
function addOption(obj)
{
var ss = document.createElement("option");
nTotal++;
ss.value = sName + nTotal;
ss.text= sName + nTotal;
obj.add(ss);
ss.selected=true;
}
</script>
<form name="form1">
<SELECT id=select1>
<OPTION>111111111111111111</OPTION>
<OPTION>222222222222222222</OPTION>
<OPTION>333333333333333333</OPTION>
<OPTION>444444444444444444</OPTION>
</SELECT>
<input type="button" value="add" onclick="addOption(select1)"><br/>
</form><script language="javascript">
sName="select";
var nTotal = 0;
function addOption(obj)
{
var ss = document.createElement("option");
nTotal++;
ss.value = sName + nTotal;
ss.text= sName + nTotal;
obj.add(ss);
ss.selected=true;
}
</script>
<script>
alert(xiaoshi.options.length);
xiaoshi.options[xiaoshi.length] = new Option("=0000=",1);
xiaoshi.options[xiaoshi.length] = new Option("=0450=",2);
</script>
<script>
function aaa() {
var zzz = document.createElement("OPTION");
zzz.text="sadasdasdas";
zzz.value="23423";
document.all.select1.add(zzz);
}
</script>
<input type="button" value="添加" onclick="aaa()"><SELECT id=select1>
<OPTION>sdfsd</OPTION>
<OPTION>sdfsdfsdf</OPTION>
<OPTION>sdf</OPTION>
<OPTION>sdfsd</OPTION>
</SELECT>