// JavaScript Document
var isIE  = (navigator.appVersion.indexOf("MSIE") != -1) ? true : false;
var isIE6  = (navigator.appVersion.indexOf("MSIE6") != -1) ? true : false;
var speed = 15; //速度，越大越慢
function wz(){
	//位置
	if (document.documentElement.clientHeight>=3000) {
    document.body.style.paddingTop=parseInt((document.documentElement.clientHeight-3000)/2) +"px";
	backgroundtop =parseInt((document.documentElement.clientHeight-700)/2)-0+"px";
  } else {
		document.body.style.paddingTop=0;
		backgroundtop ="0px";
  }
	if (document.documentElement.clientWidth<=845) {
    document.body.style.backgroundPosition = "-340px " + backgroundtop;
  } else {
		document.body.style.backgroundPosition = parseInt((document.documentElement.clientWidth-1680)/2)+"px " + backgroundtop;
  }

}
wz();
setInterval("wz()",speed);