function goEnglish() {
	if (window.location.href.indexOf("/gb/") > 0) //it is gb version now
	{
		s = window.location.href;
		re = '/b5/';
		s = s.replace(re, '/en/');
		re = 'http://translate.itsc.cuhk.edu.hk/gb/';
		s = s.replace(re, 'ht'+'tp://');
		window.location = s;
	}
	else //it is b5 version now
	{
		s = window.location.href;
		re = '/b5/';
		s = s.replace(re, '/en/');
		window.location = s;
	}
}
function goChinese() {
	if (window.location.href.indexOf("/gb/") > 0) //it is gb version now, so to b5
	{
		s = window.location.href;
		re = 'translate.itsc.cuhk.edu.hk/gb/';
		s = s.replace(re, '');
		window.location = s;
	}
	else {
		s = window.location.href;
		re = 'http://translate.itsc.cuhk.edu.hk/gb/';
		s = s.replace('ht'+'tp://',re);
		window.location = s;
	}
}