鼠标悬浮显示二级菜单效果的jquery实现

<div class="show"> 
<img src="~/images/head_icon.png" /> 

<div class="drop" style=" display:none; z-index:80000" id="profileMenu"> 
<ul> 
<li> 
<a class="pass" style="cursor: pointer" 
href='#'> 
<span>修改密码</span> 
</a> 
</li> 
<li> 
<a class="quit" style="cursor: pointer" 
href='#' 
><span>退出</span></a> 
</li> 
</ul> 
</div> 
</div>

function dropMenu(obj) { 
$(obj).each(function () { 
var theSpan = $(this); 
var theMenu = theSpan.find(".drop"); 
var tarHeight = theMenu.height(); 
theMenu.css({ height: 0, opacity: 0 }); 


var t1; 


function expand() { 
clearTimeout(t1); 
//theSpan.find('a').addClass("selected"); 
theMenu.stop().show().animate({ height: tarHeight, opacity: 1 }, 200); 
} 


function collapse() { 
clearTimeout(t1); 
t1 = setTimeout(function () { 
// theSpan.find('a').removeClass("selected"); 
theMenu.stop().animate({ height: 0, opacity: 0 }, 200, function () { 
$(this).css({ display: "none" }); 
}); 
}, 250); 
} 


theSpan.hover(expand, collapse); 
theMenu.hover(expand, collapse); 
}); 
}