从下拉列表中携带值到数据库

i have a dropdown in my html form through which i need to insert values in the database. the form is like this

<form action="add_country.php" method="post">
    <label>Category</label>
        <select name="countryname">
        <?php
            require 'connection.php';
                $sql = "SELECT * FROM country";
                $result = mysqli_query($con, $sql);

                if (mysqli_num_rows($result) > 0) {
                    while($row = mysqli_fetch_assoc($result)) 
                        {
                            $countryname=$row["countryname"];

        ?>

            <option value="<? echo $countryname;?>"><? echo $countryname;?></option>

                        <?}
                }?>
        </select>
</form> 

the back end of the form i.e add_country.php ontains the following code,

$countryname = mysqli_real_escape_string($con, $_POST['countryname']);

echo $countryname;

$sql = "SELECT * FROM country where countryname='".$countryname."'";
    $result = mysqli_query($con, $sql);

    if (mysqli_num_rows($result) > 0) {
        while($row = mysqli_fetch_assoc($result)) {
            $countryid=$row["id"];

            echo $countryid;
        }
    } 

but i am not able to fetch the countryid using the countryname (nothing gets displayed). for testing purpose when i tried to echo the countryname i got output as

africa

maybe coz of it, i am not able to match the data, however i am not so sure. can anyone tell how i can fetch the value

<form action="add_country.php" method="post">
<label>Category</label>
    <select name="countryname">
    <?php
        require 'connection.php';
            $sql = "SELECT * FROM country";
            $result = mysqli_query($con, $sql);

            if (mysqli_num_rows($result) > 0) {
                while($row = mysqli_fetch_assoc($result)) 
                    {
                        $countryname=$row["countryname"];
                        $countryid = $row["id"]; 

    ?>

        <option value="<? echo $countryid;?>"><? echo $countryname;?></option>

                    <?}
            }?>
    </select>
 </form> 

You Can Use directly id in value attribute so no need to fetch id again from table.

Use Trim() function

 $countryname =trim($_POST['countryname']);
      $country_name mysqli_real_escape_string($con,$countryname);
    echo $country_name;