i am using the following code to submit a form:

<script>
	function marktaskcomplete(){
	document.forms["markcomplete"].submit();
}
</script>
<?
		if ($_POST['markcompletevalue']=='yes'){
			include "dbconnect.php";
		$taskid=$_POST['taskid'];
		$query="UPDATE tasks SET status='0' WHERE uid='$id' AND id='$taskid'";
        $result=mysql_query($query);
		if ($result){
			echo "<script>location.href='?goto=taskmanager'</script>";
		}else{
			echo"fail";
		}
		mysql_close;
	}
	?>

and when i try to submit more then 1 form with it, it doesnt work. It will only work for the first.
can anyone help? thank you in advance

Where is your form tag part. Post your html part..

while($row=mysql_fetch_array($result)){
if($color==1){
?>
<form name='markcomplete' method=post>
<tr style='background-color:#ABD99B;'><td style='width: 200px; padding-left: 20px; font-weight: bold; font-family: arial; font-size: 10pt; text-align: left;'><a href='?goto=viewtask&id=<?php echo $row['id']; ?>' class='task'><?php echo $row['name']; ?></a></td><td style='width: 200px; font-size: 10pt;text-align: left; padding-left: 20px; vertical-align: center;'><?php
$text = $row['description'];
$text_array = explode(' ', $text);
for($x = 0; $x < 30; $x++){
echo $text_array[$x], " ";
}
?>
</td>
<input type='hidden' value=yes name=markcompletevalue>
<input type='hidden' value=<?php echo $row['id']; ?> name='taskid' id='taskid'>
<input type='hidden' value=<?php echo $id; ?> name='userid' id='userid'>
<td style='width: 200px;text-align: left; padding-left: 20px;'><?php if ($row['status']=='1'){ echo"<a href='javascript: marktaskcomplete();' class='task'> Mark complete</a>"; }else{ echo"Complete!"; } ?></td><td>
<?php  
	if($row['status']=='1' && date("dd-mm-yyyy")>$row['duedate']){ 
	echo"<img src='images/done.gif'>"; }
	else if ($row['status']=='1'){ echo"<img src='images/green.gif'>"; }
	else if($row['status']=='0'){ echo"<img src='images/checkmark.gif'>"; }
	?> </td></tr>
</FORM>
<?php
$color="2";
}else {
?>
<form name='markcomplete' method=post>
<tr style='background-color:#C7CFEB;'><td style='width: 200px; padding-left: 20px; fopnt-weight: bold; font-family: arial; font-size: 10pt; text-align: left;'><a href='?goto=viewtask&id=<?php echo $row['id']; ?>' class='task'><?php echo $row['name']; ?></a></td><td style='width: 200px; font-size: 10pt;text-align: left; padding-left: 20px; vertical-align: center;'><?php
$text = $row['description'];
$text_array = explode(' ', $text);
for($x = 0; $x < 30; $x++){
echo $text_array[$x], " ";
}
?>
</td>
<input type='hidden' value=yes name=markcompletevalue>
<input type='hidden' value=<?php echo $row['id']; ?> name='taskid' id='taskid'>
<input type='hidden' value=<?php echo $id; ?> name='userid' id='userid'>
<td style='width: 200px;text-align: left; padding-left: 20px;'><?php if ($row['status']=='1'){ echo"<a href='javascript: marktaskcomplete();' class='task'> Mark complete</a>"; }else{ echo"Complete!"; } ?></td><td>
<?php  
	if($row['status']=='1' && date("dd-mm-yyyy")>$row['duedate']){ 
	echo"<img src='images/done.gif'>"; }
	else if ($row['status']=='1'){ echo"<img src='images/green.gif'>"; }
	else if($row['status']=='0'){ echo"<img src='images/checkmark.gif'>"; }
	?> </td></tr>
</forM>
<?php
$color="1";
}
}
?>

Do not overwrite the form names and make it as separate form.