Hello. If I understand your problem correctly, you need php session variables. Those are variables whose values are shared among multiple pages. After user submits the form for the first time, you change value of a session variable and then use this code:
<form action="script.php" onsubmit="return false">
<input type="text" name="stream" style="width:200px;">
<input type="submit" value="send">
Which disables use of the button again.