Untitled

<?php
         /* Declaring two variables below */

           $message = '';
            $error = '';

      if(isset($_POST["submit"])) /*checking below for on submission*/

   {
     /*If any of the fields left empty then below msg will be displayed */
  if(empty($_POST["name"]))
  {
       $error = "<label class='text-danger'>Enter Name</label>";
  }
  else if(empty($_POST["type"]))
  {
       $error = "<label class='text-danger'>Enter Transport Type</label>";
  }
  else if(empty($_POST["mileage"]))
  {
       $error = "<label class='text-danger'>Enter Mileage on your
         transport</label>";
  }
  else  /*if all the fields are filled then below will execute */
  {
       if(file_exists('classinfo.json'))
             {
            $current_data = file_get_contents('classinfo.json');
            /*first decode json data in a variable called array_data so we
          can edit and encode back*/
            $array_data = json_decode($current_data, true);
            /*putting the contents in a var called extra that has been
          entered in the form */
            $extra = array(
                 'name'               =>     $_POST['name'],
                 'type'          =>     $_POST["type"],
                 'mileage'     =>     $_POST["mileage"]
            );
            $array_data[] = $extra;  /* putting the whole array in a new
               record in json*/
            $final_data = json_encode($array_data);
            if(file_put_contents('classinfo.json', $final_data)) /*if data
           send successfully then displaying the below message */
            {
                 $message = "<label class='text-success'>File Appended
             Success fully</p>";
            }
       }
       else
       {
            $error = 'JSON File not exits';
       }
      }
     }
         ?>
         <!DOCTYPE html>
          <html>
  <head>
       <title>Write Data to JSON file</title>

  </head>
  <body>
       <br />
       <div class="container" style="width:500px;">
            <h3 align="">Write Data to JSON file - by Sam</h3><br />
            <form method="post">
                 <?php
                 if(isset($error))
                 {
                      echo $error;
                 }
                 ?>

                   <br />
                 <label>Name</label>
                 <input type="text" name="name" class="form-control" /><br/>
                 <label>Type of transport</label>
                 <input type="text" name="type" class="form-control" /><br/>
                 <label>Mileage</label>
                 <input type="text" name="mileage" class="form-control"/>
                   <br/>
                 <input type="submit" name="submit" value="Append"/><br />