Jquery刷新页面背景图片随机变换的实现方法

<style>
 body{
                padding:0;
                background-attachment: fixed;
                background-clip: border-box;
                background-color: #666666;
                background-origin: padding-box;
                background-position: center top;
                background-repeat: no-repeat;
                background-size: cover;
                width: 100%;
                background-image:url("");}
</style>

<script type="text/javascript">
     $(document).ready(function(){
         var random_bg=Math.floor(Math.random()*6+1);
         var bg='url(images/new_feed/bg_'+random_bg+'.jpg)';
         $("body").css("background-image",bg);
});
</script>