用javascript写了个下拉菜单,如何改可以把下拉菜单打开网页是收缩的

下拉式菜单代码如下：网页打开是就是默认的下拉着，如何改可以把下拉菜单打开网页是收缩的。


<script language="javascript">
<!--
function menuChange(obj,menu)
{
if(menu.style.display == "")
{
obj.background = "http://localhost/TecoSuWeb/Images/managehide.gif";
menu.style.display = "none";
}
else
{
obj.background = "http://localhost/TecoSuWeb/Images/manageshow.gif";
menu.style.display = "";
}
}

function proLoadimg()
{
var i = new Image;
i.src = 'http://localhost/TecoSuWeb/Images/managehide.gif';
i.src = 'http://localhost/TecoSuWeb/Images/manageshow.gif';
}
-->
</script>