拉幕广告v1.4

//
// curtain advertising v1.4 power by coudly copyright
//
var _first = document.body.firstChild;
while(_first.nodeType!=1){_first = _first.nextSibling;}

var curtain = document.createElement("DIV");
curtain.style.height = "500px";
curtain.style.width = "960px";
curtain.style.margin = "0 auto 0";
curtain.style.backgroundImage = "url(guoqing.jpg)";
curtain.draw = function(){
var H = this.clientHeight;
if(H <= 51){
this.style.backgroundPosition = "0 50px";
window.clearInterval(this.timer);
this.onmouseover=function(event){
this.style.backgroundPosition = "0 0";
this.style.height = "500px";
this.onmouseout=function(){window.setTimeout(function(){curtain.timer = window.setInterval(function(){curtain.draw();}, 33);}, 2048);};
};
return false;
}
this.style.height = (H - 25) + "px";
}
window.setTimeout(function(){curtain.timer = window.setInterval(function(){curtain.draw();}, 33);}, 5000);
document.body.insertBefore(curtain, _first);