jQuery(document).ready(function($) {
  // Code using $ as usual goes here.
         
           //Background Random
           
           var backgr1="img/sfondi/01bg_city.gif"
            var backgr2="img/sfondi/02bg_city.gif"
            var backgr3="img/sfondi/03bg_city.gif"
            var backgr4="img/sfondi/04bg_city.gif"
            var backgr5="img/sfondi/05bg_city.gif"
            var backgr6="img/sfondi/06bg_city.gif"
 
            var cur=Math.floor(6*Math.random())+1
            backgr="";
            switch(cur){
                case 1:backgr = backgr1;break;
                case 2:backgr = backgr2;break;
                case 3:backgr = backgr3;break;
                case 4:backgr = backgr4;break;
                case 5:backgr = backgr5;break;
                case 6:backgr = backgr6;break;
           
            }
 
 jQuery('#main-bg').css('background', "url('"+backgr+"') no-repeat scroll center top #333333")
       //     document.write('<div id="container" style="background:url('+backgr+') no-repeat scroll 0 0 #333333" >')
       });