用js怎么获得我打勾的选择框后面的companyName

[qq_38429815]

<form method="post" name="myform"
action="<%=path%>/show/addShow!addShow.action">
<div align="center">
<table width="200" border="0" class="table">
<tbody>
<tr>
<td>ID</td>
<td>机构</td>
</tr>#companyList.companyName
<s:iterator value="companyList" id="item" status="index">
<tr>
<td><input name="id" type="checkbox" value="check">
<s:property value="#item.id" /></td>
<td name="name"><s:property value="#item.companyName" /></td>
</tr>
</s:iterator>
</tbody>
</table>
<tr>
<td> </td>
<td> <input type="button" value="提交" onclick="check();">
</td>
</tr>
</div>
</form>