Javascript move drop-down box option

Effect
<SCRIPT type = "text/JavaScript">
Function moveoptions (osource, otarget ){
While (osource. selectedindex>-1 ){
VaR opt = osource. Options [osource. selectedindex];
VaR newopt = Document. createelement ("option ");
Otarget. appendchild (newopt );
Newopt. value = opt. value;
Newopt. Text = opt. text;
Newopt. Selected = true;
Osource. removechild (OPT );
}
}
</SCRIPT>

<Div style = "float: Left;">
Selected: <br/>
<Select name = "projectmemberlist" multiple = "yes" size = "9" style = "width: 100px;" id = "projectmemberlist">
<Option value = "XXX"> x01 </option>
<Option value = "XXX"> x02 </option>
</SELECT>
</Div>
<Div style = "float: Left; margin: 0px 5px;">
<Br/>
<Br/>
<Br/>
<Input type = "button" value = "<-Add"
Onclick = "moveoptions (document. getelementbyid ('userlist'), document. getelementbyid ('projectmemberlist');"/>
<Br/>
<Br/>
<Input type = "button" value = "Remove->"
Onclick = "moveoptions (document. getelementbyid ('projectmemberlist'), document. getelementbyid ('userlist');"/>
</Div>
<Div style = "float: Left;">
Optional: <br/>
<Select multiple = "yes" size = "9" style = "width: 100px;" id = "userlist">
<Option value = "XXX"> x03 </option>
<Option value = "XXX"> x04 </option>
<Option value = "XXX"> x05 </option>
<Option value = "XXX"> x06 </option>
<Option value = "XXX"> x07 </option>
<Option value = "XXX"> x08 </option>
<Option value = "XXX"> x09 </option>
<Option value = "XXX"> x10 </option>
<Option value = "XXX"> X11 </option>
</SELECT>
</Div>

From: http://www.iecn.cn/article-html-itemid-2284-type-blog.html