if (document.images) {
   var plus = new Image();
   plus.src = "http://63.247.141.237/~cerarsmo/style/images/plus.png";
   var minus = new Image();
   minus.src = "http://63.247.141.237/~cerarsmo/style/images/minus.png";
}

function toggle(id,artid) {
    if (document.getElementById(id).style.display == 'none') {
        showdiv(id);
        minusArt(artid);
    } else {
        hidediv(id);
        plusArt(artid);
    }
}

function plusArt(artid){
   if (document.images) {
        document.getElementById(artid).src = plus.src;
   }
}

function minusArt(artid){
   if (document.images) {
        document.getElementById(artid).src = minus.src;
   }
}