jquery animate实现鼠标放上去显示离开隐藏效果

@CHARSET "UTF-8"; 
* html .showbox,* html .overlay { 
position: absolute; 
top: expression(eval(document.documentElement.scrollTop) ); 
} 
#AjaxLoading { 
border: 1px solid #8CBEDA; 
color: #37a; 
font-size: 12px; 
font-weight: bold; 
} 
#AjaxLoading div.loadingWord { 
width: 180px; 
height: 50px; 
line-height: 50px; 
border: 2px solid #D6E7F2; 
background: #fff; 
} 
#AjaxLoading img { 
margin: 10px 15px; 
float: left; 
display: inline; 
} 
.overlay { 
position: fixed; 
top: 0; 
right: 0; 
bottom: 0; 
left: 0; 
z-index: 998; 
width: 100%; 
height: 100%; 
_padding: 0 20px 0 0; 
background: #f6f4f5; 
display: none; 
} 
.showbox { 
position: fixed; 
top: 0; 
left: 50%; 
z-index: 9999; 
opacity: 0; 
filter: alpha(opacity = 0); 
margin-left: -80px; 
}

/** 
* 加载动画窗口 
* 
* @author dendy 
* @since 2013-7-19 10:13:05 
*/ 
function getLoadingHtml(msg) { 
if(!msg) msg = "加载"; 
var html = "<div id='loadingDiv'>" 
+ "<div style='height: 1325px; display: none; opacity: 0;' class='overlay'></div>" 
+ "<div style='opacity: 0; margin-top: 250px;' id='AjaxLoading' class='showbox'>" 
+ "<div class='loadingWord'>" 
+ "<img src='" + Util.getContentPath() +"/images/ajax-loader.gif'>" + msg + "中，请稍候..." 
+ "</div>" 
+ "</div>" 
+ "<div style='height: 1200px;'></div>" 
+ "</div>"; 
return html; 
} 
function ajaxLoadingInit(msg) { 
var loadingDiv = getLoadingHtml(msg); 
var h = $(document).height(); 
$(".overlay").css({"height": h}); 
var div = $("body").find("#loadingDiv"); 
div.remove(); 
$("body").append($(loadingDiv)); 
} 
/** 
* 开始显示loading，在ajax执行之前调用 
* @param msg 操作消息，"加载", "保存", "删除" 
*/ 
function startLoading(msg) { 
ajaxLoadingInit(msg); 
$(".overlay").css({'display':'block','opacity':'0.8'}); 
$(".showbox").stop(true).animate({'margin-top':'300px','opacity':'1'},200); 
} 
/** 
* 加载完成后隐藏，在ajax执行完成后（complete）调用 
*/ 
function endLoading() { 
$(".showbox").stop(true).animate({'margin-top':'250px','opacity':'0'},400); 
$(".overlay").css({'display':'none','opacity':'0'}); 
}

startLoading(); 
$.ajax({ 
type : "POST", 
url : this.url, 
dataType : "json", 
data : this.args, 
success : function (data) { 

}, 
complete : function () { 
if (self.showLoading == true) endLoading(); 
}, 
error : this.error 
});