Jquery实现table偶行变色

<table id="demo" class="ui-table">
<thead>
<tr>
<th style="width: 200px"><a id="createTime" href="javascript:void(0)">创建时间</a></th>
<th>交易号</th>
<th>金额</th>
<th>状态</th>
<th>备注</th>
</tr>
</thead>
<tbody>
<tr>
<td>2014-04-01 11:11</td>
<td>10000</td>
<td>$1128</td>
<td>有效</td>
<td>无</td>
</tr>
<tr>
<td>2014-04-05 12:11</td>
<td>10002</td>
<td>$1218</td>
<td>有效</td>
<td>无</td>
</tr>
<tr>
<td>2014-04-05 11:11</td>
<td>10003</td>
<td>$328</td>
<td>有效</td>
<td>无</td>
</tr>
<tr>
<td>2014-04-04 02:11</td>
<td>10004</td>
<td>$628</td>
<td>无效</td>
<td>无</td>
</tr>
<tr>
<td>2014-04-05 21:11</td>
<td>10005</td>
<td>$188</td>
<td>有效</td>
<td>无</td>
</tr>
</tbody>
</table>

window.onload = init;

function init(){
changeColors();//1.偶行变色

}

//偶行变色
function changeColors (){
var tr = $("#demo").find("tr");
var rowObj;
for(var i=1;i<tr.length;i++){//i从1开始，行头不算，不变色
rowObj = tr[2*i]; //得到偶数行
$(rowObj).css("background-color","#FBFBFB");//偶数行添加css样式更改背景色为#FBFBFB

}
}