How to hide menu items when the mouse moves out of the gray area_javascript skills

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Untitled Document</title> <style> *{margin:10px; padding:0} #nav{border:#ccc 1px solid; height:25px; width:198px; text-align:center; line-height:25px; margin-bottom:0} #hover{ position:absolute; height:100px; width:200px; margin-top:-2px; text-align:center; background-color:#ccc; } </style> <div id="nav" onmouseover="return hover();" onmouseout="return hover();"> <a href="##"></a>Move the mouse up</div> <div id="hover" style="display:none;" onmouseover="return hover();" onmouseout="return hover();"> <ul> <li> <a href="javascript:void(null)"></a>Menu 1</li> <li> <a href="javascript:void(null)"> </a>Menu 2</li> </ul> </div>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

]