PHP按钮不起作用

I'm trying to get a button to work , I'm not allowed to use Javascript and here's my code:

     <form id="form1" name="form1" method="post" action="course_man.php">

   for($i=0; $i <= $numcourses; $i++){
echo '<div class="new'.$i.'" id="new'.$i.'"><label>'.$course_names[$i].'</label>
    <input name="edit'.$i.'" type="submit" value="Edit" />
    <input name="delete'.$i.'" type="submit" value="Delete" /><br /></div>';

    $name= "'edit".$i."'";
    if (isset($_POST[$name])){
    echo '<input name="text" type="text" value="'.$course_names[$i].'" />';
        }
    }
   ?></form>

Now the buttons gets created and no errors are displayed, but the edit button doesnt create the textfield when clicked, what am I doing wrong?

$name= "edit".$i;
if (isset($_POST[$name])){

not: $name= "'edit".$i."'";

<form id="form1" name="form1" method="post" action="">
<?php

$course_names = array('maths','english','science','history');

$numcourses = count($course_names);

for($i=0; $i < $numcourses; $i++){

    echo '<div class="new'.$i.'" id="new'.$i.'">';

        echo '<label>'.$course_names[$i].'</label>';
        echo '<input name="edit'.$i.'" type="submit" value="Edit" />';
        echo '<input name="delete'.$i.'" type="submit" value="Delete" /><br />';

    echo '</div>';

    $name = 'edit'.$i;

    if (isset($_POST[$name])){
        echo '<input name="text" type="text" value="'.$course_names[$i].'" />';
    }
}
?>
</form>

Hope this helps, Ive tested and seems to work fine )