jquery mobile动态设置option默认选中

<script type="text/javascript">
$(document).ready(function(){
/*事件注册*/
display();
});

function display(){
/*得到服务器端的原始数据*/
var rb = <?php echo $rb;?>;
var zb = <?php echo $zb;?>;
var yb = <?php echo $yb;?>;
/*得到select标签option选项的集合*/
var dayRep = document.getElementById("dayRep").options;
var weekRep = document.getElementById("weekRep").options;
var mouthRep = document.getElementById("mouthRep").options;
/*让option选项默认选中*/
if(rb==0){
dayRep[0].selected = true;
/*调用 refresh 方法刷新样式*/
var myswitch = $("select#dayRep");
myswitch[0].selectedIndex = 0;
myswitch .slider("refresh");
}else{
dayRep[1].selected = true;
var myswitch = $("select#dayRep");
myswitch[0].selectedIndex = 1;
myswitch .slider("refresh");
}
if(zb==0){
weekRep[0].selected = true;
var myswitch = $("select#weekRep");
myswitch[0].selectedIndex = 0;
myswitch .slider("refresh");
}else{
weekRep[1].selected = true;
var myswitch = $("select#weekRep");
myswitch[0].selectedIndex = 1;
myswitch .slider("refresh");
}
if(yb==0){
mouthRep[0].selected = true;
var myswitch = $("select#mouthRep");
myswitch[0].selectedIndex = 0;
myswitch .slider("refresh");
}else{
mouthRep[1].selected = true;
var myswitch = $("select#mouthRep");
myswitch[0].selectedIndex = 1;
myswitch .slider("refresh");
}
}

</script>