Check this sample, the content to be displayed in tooltip has been bind to ToolTip propert of Label
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>Untitled Page</title>
<style type="text/css">
.tooltip
{
position: absolute;
top: 0;
left: 0;
z-index: 3;
display: none;
background-color: Orange;
color: White;
padding: 5px;
font-family: Arial;
}
</style>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script type="text/javascript" src="http://cdn.jsdelivr.net/jquery.simpletip/1.3.1/jquery.simpletip-1.3.1.min.js.txt"></script>
<script type="text/javascript">
$(function () {
$('[id*=lblItem]').each(function () {
$(this).simpletip({
content: $(this).attr('title')
});
});
});
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:DataList ID="DataList1" runat="server">
<ItemTemplate>
<asp:Label ID="lblItem" ToolTip = '<%#Eval("Price", "Price: {0}") %>' runat="server" Text='<%# Eval("Item") %>'></asp:Label>
</ItemTemplate>
</asp:DataList>
</form>
</body>
</html>
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
DataTable dt = new DataTable();
dt.Columns.AddRange(new DataColumn[2] { new DataColumn("Item"), new DataColumn("Price") });
dt.Rows.Add("Shirt", 30.34);
dt.Rows.Add("Football", 10.00);
dt.Rows.Add("Bat", 50.45);
DataList1.DataSource = dt;
DataList1.DataBind();
}
}