var activeBtn ="";
var activeBtnSrc ="";

function changeBtn(P1, P2)
        {
                 if (P1 == activeBtn) {
                 return;
                 }
                 document.images[P1].src = P2;
        }
        function setBtn(P1, P2, P3)
        {
                 if (activeBtn != "") {
                    document.images[activeBtn].src = activeBtnSrc;
                    }

                 activeBtn = P1;
                 activeBtnSrc = P3;
                 document.images[P1].src = P2;
        }