ns4 = (document.layers)? true:false
  ie4 = (document.all)? true:false
  ns6 = (document.getElementById)? true:false

function colocar_capas()
{
  
if (ns4) { 
  
  menu1Div = document.Menu1Div;
  menu2Div = document.Menu2Div;
  	 }
  
 if (ns6) { 
  
  menu1Div = document.getElementById("Menu1Div").style; 
  menu2Div = document.getElementById("Menu2Div").style; 
  
 	 } 
  
  else
  	{ 
   if (ie4) { 
  
   menu1Div = Menu1Div.style;
   menu2Div = Menu2Div.style;
  
   	    }
        }


    ancho = (document.all) ? document.body.offsetWidth : window.innerWidth

    if (ancho > 780){
		menu1Div.xpos = ((ancho/2)-(385))
    	menu1Div.left = menu1Div.xpos
	
    	menu2Div.xpos = ((ancho/2)-(250))
    	menu2Div.left = menu2Div.xpos
	}
}