<html>
<head>
<script type="text/javascript"src="
http://www.w3school.com.cn/jquery/jquery-1.11.1.min.js"></script> <script>
$(function(){
var i = 0;
var obj = $("tr td");
setInterval(function(){
obj.css("background-color", "#FFF");
obj.eq(i).css("background-color", "red");
i++;
i = (i >= obj.length) ? 0 : i;
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});
</script>
</head>
<body>
<table border="1" width="100">
<tr><td>11</td></tr>
<tr><td>22</td></tr>
<tr><td>33</td></tr>
<tr><td>44</td></tr>
</table>
</body>
</html>