PHP dynamic table - php

Question

I have to make a dynamic table n*n , the user first gives the number n and the program makes a 5*5 table with check box this part I have make it, the second part is the user checks same of the checkbox and clicks on submit and the program makes again a table 5*5 but in the place of check box which checks is colored. I have uploaded and image.
Sorry for my bad English, thanks for your time.
enter image description here
<form name="form" action="" method="get">
<input type="text" name="subject" id="subject" value="Give value">
</form>
<?php
$rows = $cols = $name = "";
if(isset($_GET['subject']))
$rows = $cols = $_GET['subject'];
if(isset($_POST['check_list']))
$name = $_POST['check_list'];
if(isset($_GET['subject'])){
echo "<form action='my.php' method='post'>";
echo "<table border='1'>";
for($tr=1;$tr<=$rows;$tr++){
echo "<tr>";
for($td=1;$td<=$cols;$td++){
echo "<td><input type='checkbox' name='check_list[]' value='value ".$td."'></td>";
}
echo "<tr>";
}
echo "</table>";
echo "<input type='submit' />
</form>";
}
// this part of code is not make the third excecution the number 3 image
echo $cols;
echo "<table border='1'>";
for($tr=1;$tr<=$rows;$tr++){
echo "<tr>";
foreach($_POST['check_list'] as $value){
if($tr == $value[td])echo "<td bgcolor='#FF0000'></td>";
else
echo "<td> </td>";
}
echo "</tr>";
}
echo "</table>";
?>