iframe载入等待

<style>
#pageloading{position:absolute; left:0px; top:0px;background:white url('../images/loading.gif') no-repeat center; width:100%; height:700px;z-index:99999;}
</style>
<div style="position:relative;">
    <div id="pageloading" style="display:none"></div>
    <iframe frameborder="0" name="home" id="home" src="" width="100%" height="700"></iframe>
</div>
<button type="button" id="button">Click Me!</button>
<script>
$("#home").on("load",function(){
    $("#pageloading").hide();
});
$('#button').click(function(){
    $("#pageloading").show();
    $('#home').attr('src','www.baidu.com');
});
</script>