function elegir_isla(id_isla){
	var num_areas = 7
	cadena = id_isla;
	
	for (i=1; i<= num_areas; i++)
	{
		cadena = "bloque_isla" + i;
		
		document.getElementById(cadena).className = "no-mostrar";
		
		/*if  (cadena == id_isla)
		{
			document.getElementById(cadena).className = "mostrar";
			alert ("igual " + cadena);
			
		}
		else
		{	
			document.getElementById(id_isla).className = "no-mostrar";
			alert ("no es igual: " + id_isla);
		}*/
	}
	document.getElementById(id_isla).className = "mostrar";
	
	
	/*if (document.getElementById(id_isla).style.display == "none")
		document.getElementById(id_isla).style.display = "block";
	else if (document.getElementById(id_isla).style.display == "block")
		document.getElementById(id_isla).style.display = "none"
	*/
	
	
}