<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
        #div1
        {
            width: 50px;
            height: 50px;
            background: red;
            float: left;
        }
        #div2
        {
            width: 200px;
            height: 200px;
            background: gray;
            float: left;
            margin-left: 20px;
            display: none;
        }
    </style>
    <script type="text/javascript">
         window.onload = function ()
         {
             var oDiv1 = document.getElementById('div1');
             var oDiv2 = document.getElementById('div2');
             oDiv2.onmouseover = oDiv1.onmouseover = function ()
             {
                 oDiv2.style.display = 'block';
                 clearInterval(timer);
             };
             oDiv2.onmouseout = oDiv1.onmouseout = function ()
             {
                 timer = setInterval(function () {
                     oDiv2.style.display = 'none';
                 },1000);

             };

         };

    </script>
</head>
<body>
<div id="div1"></div>
<div id="div2"></div>

</body>
</html>