//导航
function showdiv(divnum,divbefor){
	for(i=1;i<=divnum;i++){
			if(i==divbefor){
					document.getElementById("Sub"+i).className = "Nav_on"
			}else{
					document.getElementById("Sub"+i).className ="Nav_off";
			}
	}
}
//奥运倒计时
var DifferenceHour = -1;
var DifferenceMinute = -1;
var DifferenceSecond = -1;
var Tday = new Date("aug 8, 2008 20:00:00");
var daysms = 24 * 60 * 60 * 1000;
var hoursms = 60 * 60 * 1000;
var Secondms = 60 * 1000;
var microsecond = 1000;
function Olympics()
{
var time = new Date();
var hour = time.getHours();
var minute = time.getMinutes();
var second = time.getSeconds();
var convertHour = DifferenceHour;
var convertMinute = DifferenceMinute;
var convertSecond = DifferenceSecond;
var Diffms = Tday.getTime() - time.getTime();
  if (Diffms<="0"){
      clearTimeout(timer1);
      return false;
      }
DifferenceHour = Math.floor(Diffms / daysms)
Diffms -= DifferenceHour * daysms
DifferenceMinute = Math.floor(Diffms / hoursms)
Diffms -= DifferenceMinute * hoursms
DifferenceSecond = Math.floor(Diffms / Secondms)
Diffms -= DifferenceSecond * Secondms
var dSecs = Math.floor(Diffms / microsecond)
document.getElementById('Olytime').innerHTML='距2008北京奥运会开幕<br />还有<span>'+DifferenceHour+'</span>天<span>'+DifferenceMinute+'</span>小时<span>'+DifferenceSecond+'</span>分'; 
timer1=setTimeout("Olympics()",1000);
}