duplicate record insert on page refresh php -

whenever entered value first time , add record added whenever refresh browser pressing f5 shows message "the page you're looking used information entered..." , insert duplicate record. html code define below:

  <?php include("connection.php"); ?>     <form  role="form" method="post">                               <div class="col-md-6">                                   <div class="form-group">                                       <label>type name</label>                                       <input name="emptype" class="form-control" placeholder="employee id">                                   </div>                                   <div  class="form-group">                                       <label>type description</label>                                       <input name="typedecs" class="form-control" placeholder="first name">                                   </div>                                    </div>                                <div class="col-md-12 text-right">                                 <button type="submit" name="addtype" class="btn btn-primary">add type</button>                                 <button type="reset" class="btn btn-default">reset</button>                             </div> </form>  below php code        <?php             $emptype=$_post['emptype'];          $typedesc=$_post['typedecs'];               if(isset($_post['addtype']))               {           $query=mysql_query("insert emptype(typename,typedesc)values('$emptype','$typedesc')")or die("<script>alert('error');</script>");             echo '<script>showalert();window.settimeout(function () {hidealert();},3000);</script>'; 

does missing? please help.

suggestion: use mysqli_* or pdo instead of mysql_* functions, have written code in gave code in it.

just run select query check if record exists in database if exists not insert again.

  $query=mysql_query("select * emptype typename = '$emptype' , typedesc='$typedesc') or die(mysql_error());  if (mysql_num_rows($query)<=0) {       $query=mysql_query("insert emptype(typename,typedesc)values('$emptype','$typedesc')")or die("<script>alert('error');</script>");  }