function toggleLayer( whichLayer )
        {  
            var elem, vis;
            if( document.getElementById ) 
               // this is the way the standards work
               elem = document.getElementById( whichLayer );
            else if( document.all )
                // this is the way old msie versions work
                elem = document.all[whichLayer];
            else if( document.layers )
                // this is the way nn4 works
                elem = document.layers[whichLayer];
                
            vis = elem.style;
            // if the style.display value is blank we try to figure it out here
            if(vis.display == '' && elem.offsetWidth != undefined && elem.offsetHeight != undefined)
                vis.display = (elem.offsetWidth !=0 && elem.offsetHeight != 0)? 'block':'none';
            
            vis.display = (vis.display==''||vis.display=='block')?'none':'block';
        }
        
        function setLayerVis( whichLayer, val )
        {  
            var elem, vis;
            if( document.getElementById ) 
               // this is the way the standards work
               elem = document.getElementById( whichLayer );
            else if( document.all )
                // this is the way old msie versions work
                elem = document.all[whichLayer];
            else if( document.layers )
                // this is the way nn4 works
                elem = document.layers[whichLayer];
                
            vis = elem.style;
            // if the style.display value is blank we try to figure it out here
            if(vis.display == '' && elem.offsetWidth != undefined && elem.offsetHeight != undefined)
                vis.display = (elem.offsetWidth !=0 && elem.offsetHeight != 0)? 'block':'none';
            
            vis.display = 'block';
            
            vis.display = !val ?'none':'block';
        }