var bm        = new Array(); 
    bm[1]     = new Image(); bm[1].src = "img/Bottom_Menu_1.gif";
    bm[2]     = new Image(); bm[2].src = "img/Bottom_Menu_2.gif";
    bm[3]     = new Image(); bm[3].src = "img/Bottom_Menu_3.gif";
var bm_on     = new Array(); 
    bm_on[1]  = new Image(); bm_on[1].src = "img/Bottom_Menu_1_on.gif";
    bm_on[2]  = new Image(); bm_on[2].src = "img/Bottom_Menu_2_on.gif";
    bm_on[3]  = new Image(); bm_on[3].src = "img/Bottom_Menu_3_on.gif";

function bm_over(button){
    document.getElementById("bottom_menu_" + button).src = eval("bm_on" + "[button].src");
}// ende over

function bm_out(button){
    document.getElementById("bottom_menu_" + button).src = eval("bm" + "[button].src");
}// ende out