将td的onmouseout函数里设置一个定时器,在一定时间内移动到div上就继续显示,否则隐藏div。<html>
<head>
<title>test</title>
<script language="javascript">
var timeout = null;
function showDiv(obj,divID)
{
var iLeft = getAbsoluteLeft(obj);
var iTop = getAbsoluteTop(obj);
iTop += obj.offsetHeight;

var objDiv = eval(divID);
objDiv.style.left = iLeft;
objDiv.style.top = iTop;
objDiv.style.display = "block";
}


function hideDiv(divID)
{
timeout = window.setTimeout(function (){hideDiv1(divID)},1000);
} function hideDiv1(divID)
{
var objDiv = eval(divID);
objDiv.style.display = "none";
objDiv.style.left = 0;
objDiv.style.top = -300;
}
function getAbsoluteLeft(elem)
{
var leftPosition = 0;
while(elem)
{
if (elem.tagName == 'BODY')
{
break;
}
leftPosition += elem.offsetLeft;
elem = elem.offsetParent;
}
return leftPosition;
}

function getAbsoluteTop(elem)
{
var topPosition = 0;
while(elem)
{
if (elem.tagName == 'BODY')
{
break;
}
topPosition += elem.offsetTop;
elem = elem.offsetParent;
}
return topPosition;
}

function showSelf(objDiv)
{
window.clearTimeout(timeout);
objDiv.style.display = "block";
} function hideSelf(objDiv)
{
objDiv.style.display = "none";
}
</script>
</head>
<body MS_POSITIONING="GridLayout" topMargin="0" leftMargin="0">
<div id="myDiv" onmouseover="showSelf(this)" onmouseout="hideSelf(this)" style="DISPLAY: none;POSITION: absolute; BACKGROUND-COLOR: #33ff66">
<table border="0" ID="Table1">
<tr>
<td>DIV-DIV</td>
</tr>
<tr>
<td>DIV-DIV</td>
</tr>
</table>
</div>
<table border="1">
<tr>
<td height="100">height=100</td>
</tr>
</table>
<table border="2" cellpadding="12">
<tr>
<td>
<table border="1" cellspacing="5">
<tr>
<td onmouseover="javascript:showDiv(this,'myDiv');" onmouseout="javascript:hideDiv('myDiv');">yyyyy</td>
<td onmouseover="javascript:showDiv(this,'myDiv');" onmouseout="javascript:hideDiv('myDiv');">mmmmm</td>
<td onmouseover="javascript:showDiv(this,'myDiv');" onmouseout="javascript:hideDiv('myDiv');">xxxxx</td>
<td onmouseover="javascript:showDiv(this,'myDiv');" onmouseout="javascript:hideDiv('myDiv');">aaaaa</td>
</tr>
</table>
</td>
</tr>
</table>
</body>
</html>