chn_out = new Image();
chn_out.src = "c_h_n.gif";
chn_over = new Image();
chn_over.src = "c_h_n02.gif";

function changeImage1(num){
if (num == 1) {document.chn.src = chn_out.src;}
else{return;}
}

function changeImage2(num){
if (num == 1) {document.chn.src = chn_over.src;}
else{return;}
}