buttonImg=new Array();

for(i=0;i<=2;i++){
            buttonImg[i] = new Image();
            buttonImg[i].src="../img/k_" + i + "_on.gif";}
 
 function imageOn(n)
 {document.images['menu'+n].src=buttonImg[n].src}

function imageOff(n)
 {document.images['menu'+n].src="../img/k_" + n + "_off.gif";}