// JavaScript Document
  function swap(imgId, num) {
	
	 var curSource=document[imgId].src;
	 //var curSource=document.nav1.src;
	s = new String(curSource);
	//alert("s before " + s);
	if(num==2){
	//alert("NUM ==2");
		s=s.replace("1","2");
	}else{
		//alert("NUM ==1");
		s=s.replace("2","1");
	}
	//alert("s after " + s);
    document[imgId].src = s;
	//document.nav1.src = s;
  }