子菜单显示了，就不想隐藏了

<div id="top">
            <div id="top_1">
                <ul>                   
                    <li style="position:relative;">
                        <a href="#" id="Menu1" style="text-decoration:none; color:white;">主菜名称</a>
                        <ul id="SubMenu1" style="width: 300px; position: absolute; display: block;">
                            <li><a href="#">子菜名称一</a></li>
                            <li><a href="#">子菜名称二</a> | </li>
                            <li><a href="#">子菜名称三</a> | </li>
                            <li><a href="#">子菜名称四</a> | </li>
                        </ul>
                    </li>
                </ul>
            </div>
        </div>

 $(function () {
            $("#SubMenu1").hide();
           
            $("#Menu1").mouseover(function () {                
                showPublish();
            });
        });
       
        function showPublish() {
            $("#SubMenu1").show();
        }

#top
{
    height: 36px;
    width: 100%;        
    margin-right: auto;
    margin-left: auto;
    background-color: #006428;

    line-height: 36px;
    text-align: left;
}

#top #top_1
{
    height: 36px;
    width: 1110px;  
    line-height: 36px;
    margin-right: auto;
    margin-left: auto;
}

#top #top_1 ul
{
    margin: 0px;
    padding: 0px;
    list-style-type: none;
}

#top #top_1 li
{
    display: block;
    float: right;
    width: auto;
    line-height: 36px;
    color: #FFFFFF;
    height: 36px;
    font-size: 14px;
}