Q:

Login form in modal with Bootstrap and php not working

I am trying to implement a simple login functionality on my project, but for some reason it doesn't work as expected(or at all). 
I am not able to get the data from the name attributes from the php form, so I can proceed to the login. For some reason the data is not fetched at all. I am new to web development, so please help.
Here is my modal containing the form
 <div class="modal-content">
    <div class="modal-header">
      <button type="button" class="close" data-dismiss="modal">&times;</button>
      <h4 class="modal-title">LOGIN</h4>
    </div>
    <div class="modal-body">
      <p>Please, enter your login details.</p>
    </div>

    <form method="POST" action="homePage.php">
      <div class="row">
        <div class="col-xs-7">
          <input type="text" name="txtUserEmail" class="form-control modalForm" id="usr" placeholder=" CPR 000000-0000">
        </div>
      </div>
      <div class="row">
        <div class="col-xs-7">
         <input type="password" class="form-control modalForm" name="txtUserPassword" id="pwd" placeholder="Password">
        </div>
      </div>
      <button type="button" class="btn btn-info modalForm" data-dismiss="modal">Login</button>
    </form>

    <div class="modal-footer">

    </div>
  </div>

And here is the php for the login : 
    <?php

  session_start();

  $string = file_get_contents("users.json");

  $json_a = json_decode($string, true);

  $arr = array();
  foreach ($json_a as $json_r) {
    if ($json_r['userName']==$_POST["txtUserEmail"] && $json_r['pass']==$_POST["txtUserPassword"] ) {
      file_put_contents("prods.json",$json_r['userName']);

      if ($json_r['isAdmin']==1) {
        $_SESSION['userEmail'] = $json_r['userName'];
        header('location: adminPage.php');
        # code...
      }else{
        $_SESSION['userEmail'] = $json_r['userName'];
        header('location: patientPage.php');
      }
    }

  }
?>

Any input will be appreciated.

A:

Try This
<div class="modal-content">
<div class="modal-header">
  <button type="button" class="close" data-dismiss="modal">&times;</button>
  <h4 class="modal-title">LOGIN</h4>
</div>
<div class="modal-body">
  <p>Please, enter your login details.</p>
</div>

<form method="POST" action="homePage.php">
  <div class="row">
    <div class="col-xs-7">
      <input type="text" name="txtUserEmail" class="form-control modalForm" id="usr" placeholder=" CPR 000000-0000">
    </div>
  </div>
  <div class="row">
    <div class="col-xs-7">
     <input type="password" class="form-control modalForm" name="txtUserPassword" id="pwd" placeholder="Password">
    </div>
  </div>
  <button type="submit" class="btn btn-info modalForm" >Login</button>
</form>

<div class="modal-footer">

</div>

