<script type="text/javascript">
function vzstyle(value){
var tag = document.getElementsByTagName("link")
for(z=0;z<tag.length;z++){
if(tag[z].rel=="stylesheet"){
    tag[z].href=value
    break;
}
}
}
</script>
<select name="sel">
<option value="http://support.rusff.me/style/RusFF_Classic/RusFF_Classic.css">RusFF_Classic</option>
<option value="http://support.rusff.me/style/RusFF_FunZone/RusFF_FunZone.css">RusFF_FunZone</option>
<option value="http://support.rusff.me/style/RusFF_DeathNote/RusFF_DeathNote.css">RusFF_DeathNote</option>
</select>
<input type="button" class="button" onclick="vzstyle(document.getElementsByName('sel')[0].value)" value="ОК" />