浏览器打开层自动缓慢展开收缩实例代码

例子：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>无标题文档</title> 
<style> 
#screefull{display:block; border:1px solid #bddbf3; width:954px; padding:3px 5px 7px; margin:0 auto 10px; background:#fef9db; } 
#mostrar{display:block; width:954px; display:none;} 
#screefull a.close{ display:block; width:25px; height:20px; background:url(img/cx.gif) no-repeat 0 0; overflow:hidden; float:right; margin:16px 8px 0 0; *margin-right:5px; text-decoration:none;} 
#screefull p{ display:block; text-align:center; font-family:"Microsoft Yahei"; font-size:14px; color:#000; height:28px; line-height:28px; vertical-align:middle;} 
#screefull var{ display:inline-block; *display:inline; *zoom:1; background:url(img/wicon.gif) no-repeat 0 0; width:28px; height:28px; overflow:hidden; vertical-align:middle; margin-right:10px;} 
#screefull em{ display:inline-block; *display:inline; *zoom:1; color:#ff0000; font-family:"Microsoft Yahei"; font-style:normal;} 
#screefull span{ display:inline-block; *display:inline; *zoom:1; vertical-align:middle;} 
#screefull p a{ display:inline-block; *display:inline; *zoom:1; color:#2400ff; text-decoration:underline;} 
</style> 
<script type="text/javascript" src="js/jquery.js"></script> 
</head> 
<body> 
<!--begin:1--> 
<div id="warn" class="scree clearfix" style="display:none;"> 
<div id="screefull"> 
<a href="#" class="close" onclick="closewarn('close')">[x]</a> 
<p><span>在<em>未通过审核的网站</em>添加广告代码，将不会产生佣金。<a href="#" target="_blank" >我知道了</a></span></p> 
</div> 
</div> 
<script type="text/javascript"> 
function closewarn(type) 
{ 
$("#warn").slideUp("slow"); 
if(type == 'know') 
{ 
$.post(window.location.href,{op : 'setwarn'},function(data) 
{ 
return true; 
}); 
} 
} 
window.onload = function() 
{ 
$("#warn").slideDown(2000); 
} 
</script> 
<!--end:1--> 
</body> 
</html> 

解释上面代码段：
1、$("#warn").slideUp("slow");向上滑动， $("#warn").slideDown(2000);向下滑动
2、$.post(window.location.href,{op : 'setwarn'},function(data)
{
return true;
})
运用到了ajax 提交跟服务器进行交互，
第一个参数是请求的地址第二个是提交的参数第三个是请求成功之后调用的方法
参数op 的值是setwarn json串的格式具体运用解说看http://www.w3school.com.cn/jquery/ajax_post.asp
url 对应 locaotion.href(取得是当前页面的地址)
data对应 {op：setwarn} 字符串
success 对应函数

3、window.onload = function(){}作用一般在<text/javascript>中写的函数都要在body页面中调用，用此函数就不用等着body页面中调用就可以执行了