zajebista giereczka

<!DOCTYPE html>
<html>
    <head>

        <style>
            #pilka{
                position: absolute;
                left: 250px;
                top: 470px;
            }
            #bramka{
                position: absolute;
                left: 700px;
                top: 300px;
            }
            #gol{
                text-align: center;
                font-size: 200px;
                visibility: hidden;
            }
        </style>
        <script type="text/javascript">
            function start(){
           var rand1 = Math.floor( 1 + Math.random() * 600 );
           var rand2 = Math.floor( 1 + Math.random() * 600 );
           var x = document.getElementById("pilka");
           x.style.left = rand1+'px';
           x.style.top = rand2+'px';
            }
            function lewo(){
                var x = document.getElementById("pilka");
                var a = x.offsetLeft;
                a = a - 5 ;
                x.style.left = a+'px';
                game();
            }
            function gora(){
                var x = document.getElementById("pilka");
                var a = x.offsetTop;
                a = a - 5 ;
                x.style.top = a+'px';
                game();
            }
            function prawo(){
                var x = document.getElementById("pilka");
                var a = x.offsetLeft;
                a = a + 5 ;
                x.style.left = a+'px';
                game();
            }
            function dol(){
                var x = document.getElementById("pilka");
                var a = x.offsetTop;
                a = a + 5 ;
                x.style.top = a+'px';
                game();
            }
            function game(){
                var p = document.getElementById("pilka");
                var b = document.getElementById("bramka");
                if(p.offsetTop > b.offsetTop){
                    if(p.offsetLeft > b.offsetLeft){document.getElementById("gol").style.visibility="visible";}
                }
            }

        </script>
    </head>
    <body onload="start()">
        <input type="button" value="lewo" onclick="lewo()">
        <input type="button" value="prawo" onclick="prawo()">
        <input type="button" value="gora" onclick="gora()">
        <input type="button" value="dol" onclick="dol()">
        <img id="pilka" src="pilka.jpg" alt="pilka" height="5%">
        <img id="bramka" src="gate.png" alt="bramka" height="100px">
        <p id="gol">GOL<button id="restart" value="restart" onClick="window.location.reload()">Zagraj ponownie</button></p>
    </body>
</html>