JS获取循环表格中input的值,该怎么处理

JS获取循环表格中input的值
请问我该如何获取到鼠标点击的tr行input的值呢？
现在获取到的是始终是第一条记录。。。。。。。

JScript code

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function popUserDetail(x){
    var popUp = document.getElementById("popUserDetail");
  var h = (x.rowIndex)*20;
        popUp.style.top= 25 + h + "px";
        popUp.style.left="142px";
        popUp.style.width="200px";
        popUp.style.height="100px";
        popUp.style.visibility="visible";      
      var customerId = document.getElementsByTagName("input")[0].value;
    alert (customerId);
    }

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PHP code

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           while ($records = mysql_fetch_array($rows)) 
              { 
                  $arr = ct($records['uniqueid']);
                  $fileLastUploadTime  = $arr[1];
             
       print       '
                    <tr id="rIndex" onclick="popUserDetail(this)" onmousemove="hidePopUserDetail()">
                    <input type="hidden" name="customerId" value="'.$records[" uniqueid> 
                    <input type="hidden" name="firstLogin" value="'.$records[" firstlogin> 
                    <input type="hidden" name="address" value="'.$records[" address>                                    
                         <td width="40px">'.st($records['lastT'],$fileLastUploadTime).'</td>
                          <td width="100px">'.$records['barName'].'</td>
                          <td width="160px">'.$records['lastLogin'].'</td>
                          <td width="160px">'.date("Y-m-d H:i:s",$arr[1]).'</td>
                          <td width="150px">'.$records['endTM'].'</td>
                          <td width="40px">'.$arr[0].'</td>
                          <td width="40px" style="border-right:0;">'.$records['version'].'</td>
                          </tr>';
                  } 
 print                  '
                    <div class="popUserDetail" id="popUserDetail">
                          <table>
                          <tr>
<td id="">客户编号:</td>
<td id="cId"></td>
</tr>                                          
                          <tr>
<td>客户地址:</td>
<td></td>
</tr>
                          <tr>
<td>初次登陆:</td>
<td>备份周期:</td>
</tr>
                          <tr>
<td>联系QQ:</td>
<td>联系电话:</td>
</tr>
                          </table>
                    </div>

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