function popup(url, width, height, mode)
{
	if(!width)
	{
		width = 800;
	}
	
	if(!height)
	{
		height = 600;
	}
	
	var left = (screen.width-width)/2;
	var top = (screen.height-height)/2;
	var settings ='height='+height+',';
	settings +='width='+width+',';
	settings +='top='+top+',';
	settings +='left='+left+',';
	settings +='scrollbars=yes,';
	settings +='resizable=yes';
		
	if(mode == 'full')
	{
		// full screen mode
		settings +=',location=yes,toolbar=yes';
	}
	
	win = window.open(url, '', settings);
	
	if(parseInt(navigator.appVersion) >= 4)
	{
		win.window.focus();
	}
	
}


function check_postage_country ()
{
	if(document.getElementById('country').options[document.getElementById('country').selectedIndex].value=='')
	{
		alert('Please select your delivery location');
		return false;
	}
	return true;
}