deleting using javascript

<?php
$host="localhost"; // Host name
$username="root"; // Mysql username
$password="";     // Mysql password
$db_name="test"; // Database name
$tbl_name="emp"; // Table name

// Connect to server and select databse.
mysql_connect($host, $username, $password)or die("cannot connect");
mysql_select_db($db_name)or die("cannot select DB");
$sql="SELECT * FROM emp";
$result=mysql_query($sql);
$count=mysql_num_rows($result);
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td><form name="form1" method="post" action="">
<table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<td align="center" bgcolor="white"><strong>EmpNo</strong></td>
<td align="center" bgcolor="white"><strong>EmpName</strong></td>
<td align="center" bgcolor="white"><strong>Desig</strong></td>
</tr>
<?php
while($rows=mysql_fetch_array($result, MYSQL_ASSOC))
{

?>
<tr>
<td align="center" bgcolor="#FFFFFF"><input name="checkbox[]" type="checkbox" id="checkbox[]" value="<? echo $rows['id']; ?>"></td>
<td bgcolor="#FFFFFF"><?php echo $rows['empno']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $rows['empname']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $rows['desig']; ?></td>
</tr>
<?php
}
?>
<tr>
<td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
</tr>
<?php
// Check if delete button active, start this
if($_POST['delete'])
{
//print_r($_POST);
//exit;
for($i=0;$i<count($_POST['checkbox']);$i++)
{
$del_id = $checkbox[$i];
$sql = "DELETE FROM $tbl_name WHERE id='$del_id'";
$result = mysql_query($sql);
}

// if successful redirect to delete_multiple5.php
if($result){
echo "<meta http-equiv=\"refresh\" content=\"0;URL=h_delete.php\">";
}
}
mysql_close();
?>
</table>
</form>
</td>
</tr>
</table>

function delete()
    {
         document.getElementById('id').innerHTML="";     
     }