php - Dropdown values are not inserting in mysql -

in code dropdown values not inserting mysql database.the exam_name inserting course_code col.and course_code value not inserting in mysql.so please me.the exam_name populate examcourse when selected course_code corresponding exam_name wil display exam_course.

upload2_view.php

       <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>       <script type="text/javascript">          $(document).ready(function()              {           $(".hai").change(function()             {           var id=$(this).val();          // please find course_code, course_code not found       var datastring = 'course_code='+ id;         $.ajax        ({        type: "post",        url: "upload_view2.php",         data: datastring,         cache: false,         success: function(html)         {         $(".hai2").html(html);         }          });          });         });       </script>       </head>            <form enctype="multipart/form-data" action="<?php echo $_server['php_self']; ?>"  method="post">      file import:<br />       <input size='30' type='file' name='filename'>       select exam name:<select name=hai class="hai">       <?php      mysql_connect("localhost", "root", "") or die("error connecting database:   ".mysql_error());     mysql_select_db("slseatapp") or die(mysql_error());       $query="select  distinct exam_name examcourse";      $result = mysql_query($query);      while($nt=mysql_fetch_array($result)) {       echo "<option value='".$nt['exam_name']."'>".$nt['exam_name']."</option>";       }        ?>      </select>     <input type="submit" name="submit" value="upload"></form>     <?php      mysql_connect("localhost", "root", "") or die("error connecting database: ".mysql_error());   mysql_select_db("slseatapp") or die(mysql_error());  //upload file    if (isset($_post['submit'])) {    if (is_uploaded_file($_files['filename']['tmp_name'])) {       //import uploaded file database     $row = 1;     $handle = fopen($_files['filename']['tmp_name'], "r");     $var = $_post['hai'];     $var1 = $_post['hai2'];        while (($data = fgetcsv($handle, 1000, ",")) !== false) {     //update database values      $import="insert student_table  (id,register_number,name,course_code,subject_code,exam_name) values('".mysql_real_escape_string($data[0])."', '".mysql_real_escape_string($data[1])."','".mysql_real_escape_string($data[2])."','$var','$var1','$var2')";     $import="replace  student_table (id,register_number,name,course_code,subject_code,exam_name) values('".mysql_real_escape_string($data[0])."', '".mysql_real_escape_string($data[1])."','".mysql_real_escape_string($data[2])."','$var','$var1','$var2')";       mysql_query($import) or die(mysql_error());     }     }   fclose($handle);     echo"<script>alert('uploaded successfully');</script>";   }    ?> <br /> 

upload_view2.php

<?php            mysql_connect("localhost", "root", "") or die("error connecting database:   ".mysql_error());         mysql_select_db("slseatapp") or die(mysql_error()); ?>           <form enctype="multipart/form-data" action="<?php echo $_server['php_self']; ?   >" method="post">    <?php          @$exam_name=$_post['course_code'];            ?>          course code:<select name="hai2">            <?php         $query="select distinct course_code examcourse exam_name = '$exam_name' ";           $result = mysql_query($query);     while($nt=mysql_fetch_array($result)) {          echo "<option value='".$nt['course_code']."'>".$nt['course_code']."</option>";      }           ?>  </select> <br />