$(document).ready(function () {
  slide=setInterval(slide, 4000);
});
var current1=1;

function slide()
{
  $('#opacity1').stop();
  $('#background1').css("backgroundImage","url('/images/main-fon"+current1+".jpg')");
  $('#opacity1').animate({opacity:0},(1400), function(){
    $('#background2').css("backgroundImage","url('/images/main-fon"+current1+".jpg')");
    current1++;
    if(current1==7) current1=1;
    $('#opacity1').css('opacity','1');
  });
}