var fade_interval = 5000; // interval between changing pictures in ms
var fade_speed = 1000;    // speed of changing pictures in ms
var pictures_number = 5;  // the number of background pictures. script will switch them one by one from 1 to this number



var bg_prim_num = 1;
jQuery(document).ready(function(){
	setInterval(function(){
		var bg_prim = jQuery('.background');
		var bg_sec = jQuery('.background2');
		
		bg_prim_num = bg_prim_num > pictures_number-1 ? 1 : bg_prim_num+1;
		var bg_sec_num = bg_prim_num > pictures_number-1 ? 1 : bg_prim_num+1;
		
		var bg_prim_img = "url('/static/images/bg/bg_"+bg_prim_num+".jpg')";
		var bg_sec_img = "url('/static/images/bg/bg_"+bg_sec_num+".jpg')";
		
		bg_prim.animate({opacity: 0}, fade_speed, function(){
			bg_prim.css('background-image', bg_prim_img);
			bg_prim.css('opacity', 1);
			bg_sec.css('background-image', bg_sec_img);
		});
	}, fade_interval);
});