var oldtd = "";
var oldCaption = "";
var oldRow = "";

function showCaption(id, row_id) 
{
	// id must be passed as a number
	var caption_div = MM_findObj("caption"+id);
	var mytd = MM_findObj("td"+id);
	if(oldCaption != ""){
		oldCaption.style.display = "none";
		oldtd.className = "caption-td";
	}
	if(caption_div != null){
		caption_div.style.display = "block";
		oldCaption = caption_div;
	}
	if(mytd != null){
		mytd.className = "caption-td-active";
		oldtd = mytd;
	}
	if(oldRow != "" && oldRow != row_id){
		MM_findObj("emptycaption"+oldRow).style.display = "block";
	}
	MM_findObj("emptycaption"+row_id).style.display = "none";
	oldRow = row_id;
}