function switchNav(obj,url) {
	var thisVal = obj.value;
	var thisName = obj.name;
	if (thisVal && thisName) {
		var replaceName = new RegExp(thisName);
		var addStr = thisName + '=' + thisVal;
		if (replaceName.test(url)) {
			var pattern = thisName + '=\\d+';
			url = url.replace(new RegExp(pattern,"g"),addStr);
		} else {
			var hasQstr = new RegExp("\\?");
			url = (hasQstr.test(url))? url + '&' + addStr : url + '?' + addStr;
		}
		document.location.href = url;
	}
}