function chLang(lang) {
	var link = parent.location.href;
	var endLink = link.length;
	var i;
	var n;
	var found = 0;
	var flag = false;			// determine whether have lang or not
	var langString = "lang=";
	var lastindex = (link.indexOf("&")!= -1)?link.indexOf("&"):endLink;
	
	for(i = 0; i <= endLink; i++) {
		n = i + 3;	
		
		if (link.substring(i, i + langString.length) == langString){
			flag = true;		
			if (link.substring(i+langString.length, i+langString.length+3) == "eng") {
				chLink = link.substring(0, i + langString.length) + lang + link.substring(i+langString.length+3, endLink);				
				break;
			} else if (link.substring(i+langString.length, i + langString.length + 3) == "chi") {
				chLink = link.substring(0, i + langString.length) + lang + link.substring(i+langString.length+3, endLink);
				break;
			} else if (link.substring(i + langString.length, i + langString.length + 3) == "gbx") {
				chLink = link.substring(0, i + langString.length) + lang + link.substring(i+langString.length+3, endLink);
				break;
			}
			// default use chinese
			chLink = link.substring(0, i + langString.length) + "chi" + link.substring(i+langString.length+3, endLink);
			break;
		}				
	}
	if (!flag){
			chLink = link.substring(0, i) + "?lang=" + lang ;
	}
	//alert(lang);
	parent.location.href = chLink;
}

function go(page) {
	if (page != 0)
		self.location.href = page;
}