Hello Guys. Can you check out my codes? I dont know y i get this warning
Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\OJT\FINAL\login.php:117) in C:\xampp\htdocs\OJT\FINAL\login.php on line 130

help me guys thanks

<?php
include('dbcon.php');//para sa connection sang database

session_start();//para mag start ang session

?>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Online Evaluation</title>
    <!-- Bootstrap -->
    <link href="css/style.css" rel="stylesheet">
    <link href="css/bootstrap.min.css" rel="stylesheet">
  </head>
  <body class="body">

<nav class="alert-success navbar navbar-default navbar-static-top" role="navigation">
  <div class="container-fluid navbar-static-top">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Online Evaluation</a>
    </div>

    <!-- Collect the nav links, forms, and other content for toggling -->
    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav navbar-right">
        <li><a href="#myModal" role="button" class="btn" data-toggle="modal">Click Here for Instruction</a></li>
        <li><a href="register.php" role="button" class="btn" data-toggle="modal">Register</a></li>
        <li><a href="login.php" role="button" class="btn" data-toggle="modal">Login</a></li>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>
    <div class="container">
        <div class="alert alert-success row">
            <div class="intro">
                <h3>ESPC CORE VALUES | LOGIN</h3>

            </div>
            <div class="star">

            <div id="myModal" class="modal fade">
              <div class="modal-dialog">
                <div class="modal-content">
                  <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                    <h3 class="modal-title">ESPC PERFORMANCE APPRAISAL SYSTEM</h3>
                  </div>
                  <div class="modal-body">
                    <p><b>Direction:</b> The ESPC performance appraisal uses a five-point rating (likert) scale. This technique provides an effective method for measuring employee performance through the use of both qualitative and quantitative criteria.</p>
                    <p>In this performance appraisal technique, 5 will be considered as the highest or the most favorable and 1 will be the considered as the lowest or least favorable.</p>
                    <p>Below is the general rating reference table to be used as a guide in rating ESPC employees. You may also use the Qualitative and Quantative sheet for items that may not be rated using the table below. Appraising officers can put <b>NA (Not Applicable)</b> for some items that cannot be rated.</p>
                    <h4>ESPC General Rating Reference Table</h4>
            <div class="star col-md-12">
                <table border="1px">
                    <tr>
                        <th>SCALE VALUE</th>
                        <th>DESCRIPTION</th>
                        <th>DETAILED INFORMATION</th>
                    </tr>
                    <tr>
                                <td><h5>1</h5></td>
                                <td><h4>Unsatisfactory Performance:</h4></td>
                                <td><p>Performance must improve substantially within a reasonable period of time if the individual is to remain in this position. The employee is not meeting the job requirements.</p></td>
                    </tr>    
                    <tr>
                                <td><h5>2</h5></td>
                        <td><h4>Needs Development:</h4></td>
                                <td><p>Performance is noticeably less than expected. The employee generally meets most job requirements, but struggles to fully meet them all. The need for further development and improvement is clearly recognized.</p></td>
                    </tr>    
                    <tr>
                                <td><h5>3</h5></td>
                        <td><h4>Meets Expectations:</h4></td>
                                <td><p>Performance clearly and fully meets all the requirements of the position in terms of quality and quantity of work. It is described as good, solid performance, with thorough and on-time results. While minor deviations may occur, the overall level of performance meets all position requirements.</p></td>
                    </tr>    
                    <tr>
                                <td><h5>4</h5></td>
                        <td><h4>Exceeds Expectations:</h4></td>
                                <td><p>Performance clearly and exceeds all the requirements of the position in terms of quality and quantity of work. It is described as excellent, solid performance, with thorough and on-time results. The overall level of performance exceeds all position requirements.</p></td>
                    </tr>    
                    <tr>
                                <td><h5>5</h5></td>
                        <td><h4>Exceptional Performance:</h4></td>
                                <td><p>Performance levels and accomplishments far exceed normal expectations. This category is reserved for the employee who truly stands out and clearly and consistently demonstrates exceptional accomplishments in terms of quality and quantity of work that is easily recognized as truly exceptional by others.</p></td>
                    </tr>    

                </table>
                </div>


                    </div>
                  <div class="modal-footer">
                    <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                  </div>
                </div><!-- /.modal-content -->
              </div><!-- /.modal-dialog -->
            </div><!-- /.modal -->    
            </div>






            <div class="col-md-4">
            </div>

            <div class="col-md-4">
<?php

if (isset($_POST['submit'])) {//condition kun e click ang button
$UserName=$_POST['UserName'];//variable ang $Username kag ang $_POST['UserName'] ay value sang textbox nga UserName
$Password=$_POST['Password'];//variable ang $Username kag ang $_POST['Password'] ay value sang textbox nga Password
$result=mysql_query("select * from user where UserName='$UserName' and Password='$Password'")or die (mysql_error());//query sang database 

$count=mysql_num_rows($result);//isipon kn may tyakto sa query
$row=mysql_fetch_array($result);//ma return row sa database
$_SESSION['id']=$row['id'];//kwaon ang id sang may tyakto nga username kag password ang ibotang sa $_SESSION['member_id']


        if ($count > 0){//kun may tyakto sa query e execute yah ang code sa dalom
        header('location:evaluation.php');
        }else{
        echo "<div class='alert alert-warning'>Username and Password not Match</div>";
        }
}

?>
                <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" align="center">
                    <div class="input-group">
                      <span class="input-group-addon"><span class="glyphicon glyphicon-user"></span></span>
                      <input type="text" class="form-control" name="UserName" placeholder="Username">
                    </div>
                    <br>
                    <div class="input-group">
                      <span class="input-group-addon"><span class="glyphicon glyphicon-lock"></span></span>
                      <input type="password" class="form-control" name="Password" placeholder="Password">
                    </div>   
                    <br>
                    <span><a href="#">Forgot Password?</a></span>
                    <div class="col-md-3 pull-right">
                      <input type="submit" name="submit" class="btn btn-warning" Value="Login">
                    </div>

                </form>
            </div>




            <div class="col-md-4">

            </div>
        </div>
    </div>



            </br>
            </br>
            </br>


        <div class="clearfix"></div>
        <div class="clearfix"></div>
        <div class="clearfix"></div>
        <div class="clearfix"></div>  
    </div>
    <div class="clearfix"></div>
    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
    <!-- Include all compiled plugins (below), or include individual files as needed -->
    <script src="js/bootstrap.min.js"></script>
  </body>
</html>

Problem solve. I replace

header('location:evaluation.php');

with

echo '<META HTTP-EQUIV="Refresh" Content="0; URL=evaluation.php">';    
        exit;
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