$(window).load(function(){

        // We are listening for the window load event instead of the regular document ready.

        function animSteam(){

                // Create a new span with the steam1, or steam2 class:

                $('<span>',{
                        className:'steam'+Math.floor(Math.random()*2 + 1),
                        css:{
                                // Apply a random offset from 10px to the left to 10px to the right
                                marginLeft      : -10 + Math.floor(Math.random()*20)
                        }
                }).appendTo('#rocket').animate({
                        left:'-=58',
                        bottom:'-=100'
                }, 120,function(){

                        // When the animation completes, remove the span and
                        // set the function to be run again in 10 milliseconds

                        $(this).remove();
                        setTimeout(animSteam,10);
                });
        }

        function moveRocket(){
                $('#rocket').animate({'left':'+=100'},5000).delay(1000)
                                        .animate({'left':'-=100'},5000,function(){
                                setTimeout(moveRocket,1000);
                });
        }

        // Run the functions when the document and all images have been loaded.

        moveRocket();
        animSteam();
});