function showLayer(layernumber)
{

	i=0;
	while(document.getElementById("l"+i))
	{
		if(i == layernumber)
		{
			//alert('visible');
			document.getElementById("l"+i).style.display = "block";
			//document.getElementById("l"+i).style.visibility = "show";
		}
		else{
			//alert('hidden');
			document.getElementById("l"+i).style.display = "none";
			//document.getElementById("l"+i).style.visibility = "hide";
		}
		i++;

	}
}