// Use of this include also requires that you include sjs/sniffer.js to determine
// browser types.
// This include consists of four functions.
//  1. showLayer - one arguement, the layer ID, sets visibility to true.
//  2. hideLayer - same, sets visibility to false.
//  3. swapLayers - same except that it also requires an external global variable named
//                  currentLayer to be set at the top of the page. If the page starts with
//                  a layer visible that will be swapped that layer's ID should be put in
//                  currentLayer, as below:
//                        var currentLayer = 'rlevels';
//
//                  The currentLayer is first hidden by hideCurrentLayer and the new layer
//                  is made visible.
//  4. hideCurrentLayer - no arguement, hides the layer whose ID is stored in currentLayer.
//

       function showLayer(whichOne){
        if (is_nav4){
         eval('document.' + whichOne + '.visibility = "visible";')
        }
        if (is_ie4){
         eval('document.all.' + whichOne + '.style.visibility = "visible";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(whichOne);
         divel.style.visibility = "visible";
        }
        return;
       }

       function hideLayer(whichOne){
        if (whichOne == '' || whichOne == null) return;
        if (is_nav4){
         eval('document.' + whichOne + '.visibility = "hidden";')
        }
        if (is_ie4){
         eval('document.all.' + whichOne + '.style.visibility = "hidden";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(whichOne);
         divel.style.visibility = "hidden";
        }
        return;
       }

       function swapLayers(whichOne){
        if (currentLayer != '') hideCurrentLayer();
        currentLayer = whichOne;
        if (is_nav4){
         eval('document.' + currentLayer + '.visibility = "visible";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayer + '.style.visibility = "visible";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayer);
         divel.style.visibility = "visible";
        }
        return;
       }

       function swapLayersTwo(whichOne){
        if (currentLayerTwo != '') {
			hideCurrentLayerTwo();
	        currentLayerTwo = '';
	        return;
	    }
        currentLayerTwo = whichOne;
        if (is_nav4){
         eval('document.' + currentLayerTwo + '.visibility = "visible";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayerTwo + '.style.visibility = "visible";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayerTwo);
         divel.style.visibility = "visible";
        }
        return;
       }

       function swap2Layers(lay_1,lay_2){
        if (currentLayer != '') hideCurrentLayer();
        if (currentLayer2 != '') hideCurrentLayer2();
        currentLayer = lay_1;
        currentLayer2 = lay_2;
        if (is_nav4){
         eval('document.' + currentLayer + '.visibility = "visible";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayer + '.style.visibility = "visible";')
        }
        
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayer);
         divel.style.visibility = "visible";
        }

        if (currentLayer2 == '') return;

        if (is_nav4){
         eval('document.' + currentLayer2 + '.visibility = "visible";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayer2 + '.style.visibility = "visible";')
        }

        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayer2);
         divel.style.visibility = "visible";
        }
        return;
       }

       function hideCurrentLayer(){
        if (currentLayer == '' || currentLayer == null) return;
        if (is_nav4){
         eval('document.' + currentLayer + '.visibility = "hidden";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayer + '.style.visibility = "hidden";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayer);
         divel.style.visibility = "hidden";
        }
        return;
       }

       function hideCurrentLayerTwo(){
        if (currentLayerTwo == '' || currentLayerTwo == null) return;
        if (is_nav4){
         eval('document.' + currentLayerTwo + '.visibility = "hidden";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayerTwo + '.style.visibility = "hidden";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayerTwo);
         divel.style.visibility = "hidden";
        }
        return;
       }

       function hideCurrentLayer2(){
        if (currentLayer2 == '' || currentLayer2 == null) return;
        if (is_nav4){
         eval('document.' + currentLayer2 + '.visibility = "hidden";')
        }
        if (is_ie4){
         eval('document.all.' + currentLayer2 + '.style.visibility = "hidden";')
        }
        if(is_gecko || is_ie5up || is_ie6) {
         divel=document.getElementById(currentLayer2);
         divel.style.visibility = "hidden";
        }
        return;
       }