function getCookie( name )
{
    var nameOfCookie = name + "=";
	var x = 0;
	while ( x <= document.cookie.length )
	{
	   var y = (x+nameOfCookie.length);
	   if ( document.cookie.substring( x, y ) == nameOfCookie )
	   {
	      if ( (endOfCookie=document.cookie.indexOf( ";", y )) == -1 )
		      endOfCookie = document.cookie.length;
          return unescape( document.cookie.substring( y, endOfCookie ) );
	   }
       x = document.cookie.indexOf( " ", x ) + 1;
       if ( x == 0 )
          break;
	}
	return "";
}


function showLayer( event, layerName, num ) {
	
	var lf = 'layerF';
	var ls = 'layerS';
	var lt = 'layerT';
	
    if( event == 'over' ) {
        layObjF   = eval( document.getElementById(lf+num) );
        layObjS   = eval( document.getElementById(ls+num) );
        layObjT   = eval( document.getElementById(lt+num) );


        switch( layerName ) {
            case 'layerF' :
                layObjF.style.display = 'block';
                layObjS.style.display = 'none';
                layObjT.style.display = 'none';
            break;

            case 'layerS' :
                layObjF.style.display = 'none';
                layObjS.style.display = 'block';
                layObjT.style.display = 'none';
            break;

            case 'layerT' :
                layObjF.style.display = 'none';
                layObjS.style.display = 'none';
                layObjT.style.display = 'block';
            break;
        }
    }
}