Hey guys!
I am trying to get this countdown timer to work and trying to add a form tag that will process the timer result to be used in php but I get undefined index timer error. Here is the code for the timer:
<?php
$timer = 60;
$result = $_POST['timer'];
echo $result;
?>
<!DOCTYPE html>
<html>
<head>
	<title></title>
	<link rel="stylesheet" type="text/css" href="style.css">
	<link href="https://fonts.googleapis.com/css?family=Lobster" rel="stylesheet">
</head>
<body>
<script>
   var timer = <?php echo $timer ?>;    // 1 minute timer.... 
   var min = 0;
   var sec = 0;
   function startTimer() {
   	   min = parseInt(timer/60);
   	   sec = parseInt(timer%60);
   	   if(timer<1) {
   	   	   document.write("You have to start again!");
   	   }
   	   document.getElementById("time").innerHTML =  + min.toString() + ":" + sec.toString();
   	   timer--;
   	   setTimeout(function() {
          startTimer();
   	   }, 1000);
   }
     function stopTimer() {
     
     alert("Thank you for completing the test. You finished the test at: " +  min.toString() + ":" + sec.toString());
     	  
         var result = document.getElementById('time').innerHTML;
         document.getElementById('input').value = result;
    //   window.location.href = "update.php";
     }
</script>
<form>
<div class="timer">
<h1>Welcome to Timertrone.</h1>
<br></br>
<form action="" method="POST">
  <b>Time Left:  </b> <span class="timer_display" id="time"> ...</span>
<input type="text" name="timer" id="input">
<h1 id="buttons"></h1>
<button type="button" name="start" onclick="startTimer()">Start</button>
<button type="button" name="stop" onclick="stopTimer()">Stop</button>
<button type="submit" name="submit" >Submit</button>
</form>
</div>
</div>
</body>
</html>