var Ary=new Array();
function showPic (obj,whichpic) {
    if (!obj.set){
     obj.set=true;
     Ary[Ary.length]=obj;
    }
    for (i=0;i<Ary.length;i++){
     Ary[i].className='notselected';
    }
    obj.className='selected';
	if (document.getElementById) {
		document.getElementById('mainimg').src = whichpic;
	}
}