How to set alternate row color for an iterated table in php?

I am using PHP and I am iterating a table with a result array ... I want to add row color and alternate row color to it.... How to do so? Any suggestion...

<table  id="chkbox" cellpadding="0" cellspacing="2" 
               width="100%" class="table_Style_Border">
<tr>
<td style="width:150px" class="grid_header" align="center">RackName</td>    
   <td style="width:150px" class="grid_header" align="center">LibraryName</td>  
<td style="width:200px" class="grid_header" align="center">LibrarianName</td>
<td style="width:200px" class="grid_header" align="center">Location</td>
        <td style="width:1%" class="grid_header"></td>


    </tr>

     <? if(isset($comment))
           { echo '<tr>
      <td class=table_label colspan=5>'.$comment.'</td></tr>'; } ?>
    <?php foreach($rackData as $row) { ?>
    <tr>
        <td align="left" class="table_label">
                <?=$row['rack_name']?>
        </td>
        <td align="left" class="table_label">
                <?=$row['library_name']?>
        </td>
        <td align="center" class="table_label">
                <?=$row['librarian']?>
        </td>
        <td align="center" class="table_label">
                <?=$row['location']?>
        </td>
        <td align="center">
            <input type="checkbox" name="group" id="group" 
  value="<?=$row['rack_id']?>" onclick="display(this);"  > 
        </td>

    </tr>

  <?    } ?>
    <table>

EDIT:

<?php foreach($rackData as $key =>  $row) { ?>
        <?php printf('<tr class="%s">', ($key % 2) ? : 'rowcolor' : 'alternaterowcolor');?>

It doesn't seem to take your syntax....

ERROR:

Parse error: syntax error, unexpected ':' in D:\xampp\htdocs\codeigniter_cup_m开发者_开发知识库yth_new\system\application\views\rackdetails.php on line 238

Use modulo

<?php foreach($rackData as $key => $row) { ?>
    <?php printf('<tr class="%s">', ($key % 2) ? 'odd' : 'even'); ?>
    // ...

Then you can define CSS classes with the names .odd and .even and given them the background-color you want the rows to alternate with.

With modern browsers (read: not IE 8 or lower) you can also do it directly in CSS with the :nth-child pseudo class:

tr:nth-child(even) { background-color: #FFF; }
tr:nth-child(odd) { background-color: #EEE; }

To streamline your server code you could use javascript to highlight your rows and add mouse over/out handlers to the rows to do whatever you want.

Very easy to do with jquery and many examples.

<?php 
include("BLL/index.php");
$objBLL = new BLL();
$result = $objBLL->SelectQuery();
$ID = $i;
$i = 1;
?>
<table border="1" width="50%">
    <tr>
        <td>ID</td>
        <td>NAME</td>
        <td>DESCRIPTION</td>
    </tr>   

<?php
 while ($row = mysql_fetch_assoc($result)) {
  if ($i % 2 != 0) {# An odd row 
    $rowColor = "orange"; 
    echo '<tr bgcolor="' . $rowColor . '"><td >' . $row["ID"] . '</td><td >' . $row["Name"] . '</td><td >' . $row["Description"] . '</td></tr>' . "\r\n";
    $i++;
  }else{  # An even row 
    $rowColor = "green";
    echo '<tr bgcolor="' . $rowColor . '"><td >' . $row["ID"] . '</td><td >' . $row["Name"] . '</td><td >' . $row["Description"] . '</td></tr>' . "\r\n";
    $i++;
  } 
}
?>  
</table>