var Tday = new Date("Dec 22, 2012 00:00:00");   //**倒计时时间点-注意格式
var microsecond = 1000;
function clock()
{
	var time = new Date();
	var Diffms = Tday.getTime() - time.getTime();
	var dSecs = Math.floor(Diffms / microsecond);
	var Dtip =  "what's this? -->> ";
	unknown.innerHTML = Dtip + dSecs;
	unknown_nav.innerHTML = Dtip + dSecs;
	setTimeout("clock()",1000);
	return true
}