js判断鼠标同时离开两个div

纠结了两天，憋出了个蛋，欢迎拍砖！！！
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
ul{margin:0;padding:0}
li{position:relative;margin:0;padding:0;;}
.grid{background:#ccc;width:100px;height:100px;;}
.f{background:#333;width:200px;height:200px;position:absolute;top:0;left:100px; display:none}
</style>
<script type="text/javascript" src="http://mat1.gtimg.com/www/js/tcomment/jquery-1.6.2.min.js"></script>
<script type="text/javascript">
jQuery(function(){
     window.a=0; window.b=1 ; //同为1隐藏弹层 
    $(\'ul\').delegate(\'.grid\',\'mouseover\',function(){ // 鼠标放在头像上
        if($(\'.f\')){
            $(\'ul\').append(\'<div class="f"></div>\')
            $(\'.f\').css({top:$(this).offset().top})
        }
        window.a=0;
        $(\'.f\').show();
    })
    
    $(\'ul\').delegate(\'.f\',\'mouseover\',function(){// 鼠标在弹层上
            window.b=0;
        });
    $(\'ul\').delegate(\'.grid\',\'mouseout\',function(){// 鼠标离开头像
        window.a=1;
    })
    $(\'ul\').delegate(\'.f\',\'mouseout\',function(){// 离开弹层
        window.b=1;
    });

    setInterval(function(){//console.log(window.a +" "+ window.b +" "+ window.c);
        if(window.a&&window.b){
            $(\'.f\').hide();
        }
    },100)
})
</script>
</head>

<body>
<ul>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
    <li><div class="grid"></div></li>
</ul>

</body>
</html>