var oldRow;
    var oldRowClassName;

    function onMouseOver(tr, evenRow) {
            oldRowClassName = tr.className;
            oldRow = tr;
            if(evenRow) {
            	tr.className = "mouseOverEvenRow";
            } else {
            	tr.className = "mouseOverOddRow";
            }

    }

    function onMouseOut(tr) {
            if(oldRow != null) {
                oldRow.className = oldRowClassName;
                oldRow = null;
            }
    }