var nc = (document.layers) ? true:false
var ie =   (document.all) ? true:false
var n6 = (document.getElementById) ? true:false
 
 function mostrarMenu(id) 
 {
 if (ie)
  		{
	   disp = document.all(id).style.display;
	   if(disp == "block")
   			 document.all(id).style.display = "none";
 		else
 		   document.all(id).style.display = "block";
	   }
 	 	else if (nc)
  			{
	    	 disp = document.layers(id).style.display; 
			 if(disp == "block")
		    	document.layers(id).style.display = "none";
	  		else
	    		document.layers(id).style.display = "block";
	  		}
		  else if (n6)
  			{
	       disp = document.getElementById(id).style.display;
		   if(disp == "block")
			   document.getElementById(id).style.display = "none";
	  	   else
    			document.getElementById(id).style.display = "block";
	   		} 
			else
			{
	       disp = document.getElementById(id).style.display;
		   if(disp == "block")
			   document.getElementById(id).style.display = "none";
	  	   else
    			document.getElementById(id).style.display = "block";
			}
		
 }