function show_div(id){

	var element = document.getElementById(id);
	
	if ( element != null){
		document.getElementById(id).style.display = 'block';
	}

}


function hide_div(id){

	var element = document.getElementById(id);
	
	if ( element != null){
		document.getElementById(id).style.display = 'none';
	}
}