function filter_newsletters()
{
	

	cat = document.getElementById('cat_select')
	cat_id = cat[cat.selectedIndex].value;
	
	month = document.getElementById('month_select')
	month_val = month[month.selectedIndex].value;
	
	year = document.getElementById('year_select')
	year_val = year[year.selectedIndex].value;
	
	location='?cat_id='+cat_id+'&month='+month_val+'&year='+year_val;
	
}