function hidediv( _levelId ) {
        var thisLevel = document.getElementById( _levelId );
        thisLevel.style.display = "none";
        }

function showdiv( _levelId) {
        var thisLevel = document.getElementById( _levelId );
        if ( thisLevel.style.display == "none") {
                 thisLevel.style.display = "block";
                }
        else {
                hidediv( _levelId);
                }
        }